The Plant Kingdoms

Common Knowledge

The Shendru are a species of omnivirous tree.  Their branches are subtly articulated, and they have a toothed maw atop their barrel-like body.  They have the ability to enslave other types of plants, and are sometimes served by brackles or treants.  Although they don't have nooses, they're sometimes known as hangman trees by very old pedants.

Brackles are a species of humanoid plants that are capable of spitting thorns.  They are narrow and sharp, all elbows and fluted snouts.  They travel the world looking to exchange pollen before dying in winter, as each brackle only lives a single year.

(I'm retconning my Brackles.)

Marilanths are another species of humanoid plant.  They are large masses of flower-covered vines with four clumsy arms.  Like Brackles, they are itinerant, travelling the world while looking for places to set down their roots.  They sometimes sell drugs.

from the 2nd edition Monstrous Manual

Uncommon Knowledge

We now know that they are both members of the same species: the Shendru.

This is not common knowledge because brackles and marilanths don't speak of their sexual habits, a cultural taboo that is even stronger among Shendru than among humans.  (Shendru are not a monoculture, but this is true among the cultures of Mothmoria and Greenmarch, which are two populous "cities" of the Shendru.)

Shendru Biology

Brackles tend to wander.  Perhaps they just want to experience as much as they can in the brief year before they die.  Perhaps they're driven by a desire to pass their pollen on to as many marilanths as they can.  Perhaps they are driven to protect the groves and farmlands of their families by searching out threats.  Or most likely, all of the above.

They have faces like seahorses and don't eat very much.  They lose weight steadily over their year of life, and are usually quite gaunt by December, when most of them die.

Brackles write very good poetry.  In winter, many brackles choose to inscribe their death poems along the lengths of their limbs.

Marilanths can grow much larger than a human if food is plentiful.  In this case, they usually also grow a second pair of arms.  Marilanths also tend to wander, although perhaps not as far afield as brackles.  They tend to be more interested in gustatory experiences.

All Shendru can talk to plants, but marilanths are exceptionally persuasive.  This gives them a good deal of control over their farms.

Brackles who form strong bonds with marilanths will usually "marry" them.  This involves collecting ingredients for a feast, a night of dancing, and then a meal that includes the brackle.  There few cases where a brackle and a human have fallen in love have followed the same pattern.

When a marilanth is ready to settle down, or when she begins to starve, she sends down roots and becomes a tree.  Her children are the product of her own eggs as well as the pollen that she collected over her lifetime.  (She can continue receiving pollen as a tree, but in some cultures this is considered unseemly, as shendru exist in a dreamlike state most of the time, and not fully aware of everything that happens around them.)

Shendru trees can grow brackles and marilanths whenever they wish, but they can also grow fruits that imitate the substances that they have eaten over their whole lives.  A shendru who has tasted coffee can grow a caffeinated fruit that tastes similar.

Marilanths also possess this ability, albeit in a much smaller capacity.  This is why they often sell drugs, which is why they are often chased away from civilized lands.

Shendru Lore

The scholars will tell you that Shendru were created by the old spirits of the forest, in order that they might fight back against the incursions of mankind.  Treants were too slow to grow, too slow to anger.  Why else would brackles have such deadly thorns?

The Church will tell you that the Shendru were created to serve humanity, but when we accepted sins into our hearts, the forests turned against us.  Why else would they bear such pleasing fruit?

The Elves will tell you that the Shendru were bred to be farmers.  What better to tend to a farm than the farm itself?  It fits their model.

Shendru Cities

The two major homelands of the Shendru are Mothmoria and the Greenmarch.

<sidebar>When people invent their own races, there are two things that annoy me.  First, presenting any intelligent species as a monoculture.  Second, not giving them any settlements of their own, or only giving them a single place of origin.</sidebar>

The Mazes of Mothmoria

The Shendru of Mothmoria are waiting for their masters, the giants.  They have been entrusted with the gardens, and they have kept them immaculate for centuries.  They have done more than maintain, actually--they have expanded.  Every generation of caretakers have measured their success in the increase of Mothmoria.

It is a garden maze the size of a forest, filled with hedges, contemplation pools, mossy statues, iron gates, and softly bubbling fountains.  With all of the local plants charmed by the Shendru, weeds don't even poke up between the stones.

Mothmoria is beautiful, tranquil, and useless for anything except for quiet contemplation.  Somewhere in the middle of it, behind the endless terraces of waterfalls and lilies, are the stone houses of the giants.  They are quiet now, even the Shendru have only the vaguest idea of what is contained within.  They aren't allowed in the houses.

To the west is the Great Forest Yava, the eternal stronghold of the elves and the most beautiful place in the world.  They fight a slow war against the Shendru of Mothmoria.  Both sides are loathe to disrupt the peace of their forests, and so the war is fought at the pace at which trees grow.  Outsiders could be forgiven for thinking that this war is gentler or less bloody.

The Dukes of the Greenmarch

The Shendru of the Greenmarch are organized into plantations, each one a zone of land controlled by a Duke or Duchess.  Each one has a longhouse built around their progenitor.  The brackles and marilanths of that place are organized along familial lines, with the male brackles traded among houses as workers, soldiers, transporters, or arranged husbands.

Visitors are often struck by how human the society seems.  They even have their own currency: black brass coins.

And humans are welcome there.  The Greenmarch conducts a fair amount of trade, in crops, spices, cotton, and wool.  (Their power over plants simplifies many of these enterprises.)  They even maintain a silver mine.  Most of them are Hesayan, although doctrine dictates that they lack the seventh soul.

There are a few oddities: the bounty on bees (to prevent accidental pregnancies), the ritualistic skirmishes between brackles trying to earn fame, the drug tolerance contests, and/or the mutually cannibalistic friendship ceremonies (of which humans are expected to participate.

Humans are given new names when they arrive in the Greenmarch.  Human names are considered vulgar within their borders.  Human reproduction is also a mild taboo (since many of the younger brackles don't know about it), and it is polite to pass on the mythology that humans reproduce the same way that Shendru do.

source unknown?

Kasrosassus and the White Woods

Pale trees lean over streams lined with dolomite.  Their leaves are red.  White roots grip chalky hillsides, and the straw-yellow grasses are as thin as a newborn's hair.

The ecology of the White Woods is essentially vampiric.  From the smallest mouse to the thickest bear.  Even the deer suck their meals.  Mostly hairless, entirely albino, and with a universal aversion to sunlight, which pierces the thick fog only rarely.  On especially bright days, most of the animals retreat into the extensive karst caves that dot the forest, like antelope huddling near a watering hole during the dry season.

At the center of it all is Kasrosassus, a botanic titan whose red eyes can see the dead, and whose crocodile mouth vomits forth huge clouds of fog.  Inside his vast vegetable bulk nest families of bats.  Kasrosassus claims to be the progenitor of all vampires.

Kasrosassus is perhaps the most powerful necromancer in the world.  It is said that Shadoom plucked his seed from the darkness behind the sun and planted it in Centerra.  Even Queen Yama studied at the knee of the leviathan.

All creatures that die within the White Woods immediately rise as undead under the control of Kasrosassus.  They walk to the middle of the woods, where Kasrosassus plucks them up and sucks them dry.  The dessicated undead is then stored in the cool, dry caverns beneath his roots, where he stores the rest of his armies.

In bygone days, Kasrosassus marched on the cities of Brynth and Belgast.  His "sons" were white trees, conveyed in hundred-wheeled chariot-urns, pulled by an ever-growing army of undead.  Their powers extended for miles around each one.

The Church broke the Sons of Kasrosassus into splinters, and drove the hordes back into the pale arms of the White Woods.  They never uprooted the great necromancer from his stronghold, but he has not ventured from his stronghold in any of the days since.

Travelers who would pass the White Woods would be wise to seek safe passage.  Those who would do so are advised to bring a human corpse with them as they travel (or make their own).  As soon as they cross the threshold of the forest, the corpse will sit up and speak, and they may communicate with the great necromancer directly.

The usual fee is a single cow for every traveler.  Simply slit their throats and they will walk off themselves.

Triple X Depletion: A Unified Depletion System

Everyone else is writing good posts about depletion so here's my take on it.

Here are the expendable/depletable resources that adventurers rely on:

1. Food, water

2. Torches, lanterns

3. Arrows, sling stones, weapons?, armor?

Triple X

Whenever something gets depleted, put an X next to it.  After three Xs, it's gone.  This is pretty close to "each slot can hold a bundle of three rations" but is more unified and probably more elegant.

Food - Depletes when you eat lunch or sleep.  Replenishes when you buy more: 1 silver to remove 1 X.

Water - Depletes when you eat lunch or sleep.  Replenishes automatically when you are out of the dungeon, unless your DM tells you otherwise.  (It's assumed that water sources will be available, or at least, it isn't usually interesting to track down where the nearest creek is.)

Note: When you eat lunch, you can choose to mark off either food or water.  When you rest for the night, you need to mark off both.

Torches - Depletes according to the depletion die (rolled every 30 minutes in a dungeon).  Replenishes when you buy more: 1 silver to remove 1 X.

Lamps - Depletes according to the depletion die (rolled every 30 minutes in a dungeon).  Replenishes when you buy more: 50 silver to remove 1 X.

Note: For simplicity's sake, I'm just going to assume that all of the lamps are basically slow-burning molotovs, where the fuel container and the lamp are the same thing.  A lit lamp can be thrown just like a molotov.

Bow - After every combat in which you used arrows, flip a coin. On tails, your arrows deplete.  Replenishes when you buy more: 1 silver to remove 1 X.

Sling - Whenever you fire a sling stone, you gain a single depletion.  Replenishes whenever you have a moment to pick up some stones or stony debris.  (Basically as soon as combat ends, in your average dungeon.)

Melee Weapons - Whenever you roll a 1 or a 20 on an attack roll, a melee weapon gains an X (in addition to the other effects of the fumble).  It breaks when it gains the third X.  Replenishes whenever you stop by a blacksmith: 1 silver to remove 1 X.

Armor - Whenever you roll a critical fumble on a Defense roll, your armor gains an X (in addition to the other effects of the fumble).  When you gain 3 depletions, you lose two points of AC, erase all of the Xs, and your armor takes up one slot less.  (Basically, your plate just turned into chain.)

Simplified Armor

This is what I'm running with these days.

Leather - 1 slot, AC 12, swim automatically

Chain - 2 slots, AC 14, Str check to swim

Plate - 3 slots, AC 16, sink automatically, must be custom-made

Each character has a number of slots equal to Str.

You can also build your armor as a hodgepodge, from armor pieces.  Each regular armor piece gives you +1 AC, while well-fitted armor pieces can give you +2 (usually requires time and proper tools), up to a maximum of AC 15.  Only custom-made plate can give you AC 16.

Depletion Rolls

Every thirty minutes of dungeoneering, the DM rolls a d20.  On a 1-5, all light sources deplete.

Note: I've played around with more complicated versions of this.  6-10 used to be spell expiration, 11-15 used to be a morale challenge (e.g. hirelings get scared).  I might bring those back, but this seems sufficient for now.  Light is what I care about most.  (Although the morale challenges were interesting.)

(Brian Harbron write one that I liked, based on some Chris McDowall stuff.)

Encounter Rolls

While the DM rolls for depletion, the players roll for wandering monsters.  Basically, roll a d20:

1-3 - encounter

4-6 - tracks

Encumbered characters increase the chances of a wandering monster.  Rangers increase the chance of finding tracks.  A full explanation is detailed here.

More Rules

Whenever you use an item for a special use, it automatically depletes.  Using a sword to chop through a door, using water to put out a fire, dropping food to distract monsters, etc.

If you loot the arrows off a dead archer, your bow regains one depletion.

Magic arrows take up inventory spaces.  You can bundle them, though, as long as they're the same type.

Magic weapons and armor last twice as long, so one depletion gives an '\', while the second depletion turns it into an 'X'.  Magic weapons and armor can only be repaired by insane blacksmiths.  The price for repair is never money.

Shitty weapons and armor break instantly as soon as they gain their first X.  Scavenged weapons have 0-2 depletions when they are looted.

If you need to convert depletions into exact amounts for some reason, then assume that each X equals

• A meal's worth of rations.
• A pint of water.
• 5 arrows.
• 1 sling stone.
• A torch (2 hr).
• A pint of lamp oil (2 hr).

Attack Roll Fumbles

It is possible to deplete your weapons and armor by rolling fumbles on your Attack and Defense rolls, respectively.  That sword might break sooner than you think!

Here's what I'm running these days.

Critical fumbles represent a tactical misstep that gives an opening to an enemy.  When you roll a critical fumble, the most threatening adjacent foe takes advantage of it.  Yes, this means that is possible to fumble against a goblin and get whacked by the ogre adjacent (perhaps you turned your back on him, or stumbled).

Enemies have three basic options, and intelligent enemies will choose whichever one makes the most sense at the time.  Stupid enemies will behave more randomly.

• Free Attack (by the most threatening adjacent opponent).
• Free Combat Maneuver (such as tripping, disarming, etc).
• Free Sunder Attempt (a type of combat maneuver).

If a weapon would gain a fourth depletion, it instead shatters into pieces.  

If you show up with a dragon-killing spear, expect the dragon to spend a turn biting that shit in half (assuming they don't just knock it out of your hand and then stand on it).

The number of depletions depends on the size and strength of your opponent.

Human (HD 1) = 1 depletion
Ogre (HD 4) = 2 depletions
Giant (HD 7) = 3 depletions (instantly breaking a brand-new weapon)

Regular weapons accumulate these depletions automatically, but magic weapons have a 3-in-6 chance of ignoring them.  Roll each separately.  (So if a dragon attempts to sunder your magic spear, roll four times, with each roll having a 3-in-6 chance of resulting in a depletion.)

Golems specialize in destroying weapons, and will always choose to sunder your weapon if you roll a fumble against them.  They are terrifyingly good at it.

Golem (HD 5) = 5 depletions

Special Weapons

This also opens the door to modulating weapons according to durability.

Chargale blades are made from a special type of clay that is baked for years (or decades).  They deal damage as a regular sword, but they will never break.

Crysmere blades deal damage as if they were a magic sword, but they have the durability of a regular sword.  They cannot be repaired.  You can cast spells (of any range) through crysmere weapons.  (Crysmere arrows are especially coveted for this reason.)

Both of these types of blade are immensely valuable.  You may just want to sell them.

Drume and the Egg

Drume is a city on the Sea of Fish.  For the last few generations, it has avoided any major wars, plagues, famines, and excommunications.  They have a merchant fleet supported by airships.  They have the highest literacy rate in the world, and have the largest secular school: the Pillar of Academy.  Their politics are mild and very accepting of other cultures.

This is all very unusual.

The architecture is late Neropic, with many buildings resembling bulbs and squashed domes, while others are mudbrick with exposed wooden supports.  The cuisine features a lot of rice and seafood (especially squid), with a healthy influx of cuisine from their three biggest trading partners: Abasinia, Kaladar, and Charcorra.

Drume is also the only city where you'll find a superhero.  Her name is Lulu, and she fights crime.  She flies across the city on magic wings, and she wears a squid mask. Everyone loves Lulu.  Children wear imitation masks; sailors get tattoos.

Hexaplex cichorium

The Quadrumvirate

The city is ruled by the Quadrumvirate: four wealthy families.  Every five years, one of the seats is up for election.  Each family is then responsible for providing someone to sit at the Quadrumvirate.

Craftau Warlov - The Warlovs were founding members of the Pillar of Academy.  Mages, heretics, rebels, and priests.  A family of dissidents.  They have awkward family dinners, but they do their best to present a unified face.  Craftau is a mage, and is usually accompanied by her husband, an exiled knight from Noth.

Guster Lethok - The Lethok family deals in airships, and holds the second membership.  The matriarch of this family, finally grow too old to attend, appointed her youngest son to fill the role.  Guster has spent most of his life abroad, studying.  While the Lethok family is popular, Guster is unknown, and therefore untrusted.

Kashtan Larksmith - A family that deals in banking and land ownership.  Kashtan is fiercely loyal to the city, and wary of outside influence.  She's killed at least two people in duels.

"Eb" Alazed - An ancient and enormous old man, who operates a dozen merchant ships.  His sons manage most of Drume's modest navy.

Hatred of Orcs

Drume was conquered by orcs and did not win its freedom until a century ago.  Noth helped.

The city's famous tolerance does not extend to orcs, which are despised and hunted at every turn.  There are a few remnants of orcish rule in the city.  Shumish art tends to mirror the brutality of orcish art.  A number of orcish words persist in the Shumish vocabulary.  And the rapid assembly of human thrones persists as a popular sport.

The Hum

On very quiet quiet nights, you can can hear it.  Not in your ears, but in your bones.  A subsonic thrum that permeates everything.

Visitors hate it.  It keeps them up at night.  Locals speak fondly of it, for the most part.

Most people are convinced that it is caused by something deep in the Pillar of Academy.  They are correct.

an Ionic columm

The Pillar of Academy

Looks almost exactly like a Ionic pillar, magnified a hundred times.  A stone skyscraper of antediluvian construction, every floor marked by a row of pin-prick windows lancing their light out into the night sky. 

The top of the Pillar emits steam.  Illuminated by light, the cloud is bright enough to illuminate the city at night.

The basement of the Pillar is filled with light.  Most assume that it is some sort of mechanism that the mages invented.

The deeper down you go, the brighter it gets.  Blindness becomes a risk.  The marble walls become reflective.  The light becomes painful even through closed eyelids.  Eventually the heat becomes an issue as well.  The lower levels of the basement are where the Pillar keeps its secrets.

The Egg of Drume

According to anyone's best guess, the Egg is an extraterrestrial mollusk.

It was found in the lake of Zaotan a long time ago, and stolen from the dragon Tar Lath Lien.  (This was back when the Egg was still small enough to be hidden under a cloak.)

It sits in the middle of a secret dungeon beneath the known dungeon beneath the Castle of the Pearl.  It has grown so much in the last 50 years that the vast crenellations and creases of its shell form a small labyrinth around the animal inside.

The central chamber resembles the inside of a conch shell, with the far wall filled with a folded, protruding shell.  This wall is full of symmetrical apertures, from which the Egg can extrude its nearly-translucent tentacles.  Somewhere in the pulpy mass of its cryptic head is a five-toothed mouth, surrounded by what can loosely be described as a face.

The Egg eats a steady diet of eggshells and fish heads (so many fish heads).  It communicates through local telepathy and is the most intelligent creature in Centerra.

Here is the reason for its genius: it is capable of absorbing the intellect of any fresh brain that it consumes, which is then integrated and aligned with the Egg's own goals.  It is also utterly evil.

When asked about what it would do if it were given a choice, the Egg described a scenario that involved the annihilation of all other life on the planet except for its own, the consumption of all resources, and the launch of its offspring into the ether.  The ultimate justification for this was to minimize ignorance and suffering (two cornerstones of the human condition) and also to prepare for the end of the universe.  (The Egg intends to survive.)

The Egg is honest.  If it were capable of lying, it hasn't revealed it yet.

Credit for the city's success lays squarely with the Egg.  The Quadrumvirate ask the Egg questions, and it answers.  "What would the outcome of this taxation policy be?" "How much should we trust Noth?"  "Where should we deploy our Navy?"

It doesn't make decisions.  It simply provides answers.

The Quadrumvirate has had to make very few concessions in order to secure the cooperation of their prisoner.  As the Egg will point out, this is unjust.

Assassins have attempted to kill the Egg on past occasions.  They have all failed.  Even without any psychic powers, the Egg is fully capable of defending itself. 

And of course, it's usually trivial to figure out who hired the assassins once the Egg starts eating heads.

Containment

A huge array of containment systems have been arrayed around it, both physical and magical.  Dozens of barriers prevent the escape of Drume's most important citizen.  The creature's brain is also tattooed with dozens of explosive runes, set to explode if the right command word is uttered.

The Egg actually cooperated in designing its own prison.  It gave good advice, and the mages who designed it were impressed by its thoroughness and innovation.

Quest idea: thieves hire you to break into (what they assume to be) the secret vault beneath the Castle of the Pearl.

There are also many rules in place to prevent the Egg's abilities from being abused.  No one may speak to the Egg unless the entire Quadrumvirate is present.  Questions are best formulated by telling the Egg what your objective is, and then asking the best way to achieve it.  And lastly, no one should be fed to the Egg who might know the details of the Egg's prison.  (This last rule has only been slightly broken a couple of times.  Sometimes its important to know what a mage was lying about.)

The Hum, Part 2

Craftau Warlov manages the Benevolence Engine beneath the Pillar.  It is responsible for five things.

1. The everpresent, luminous clouds above the city and the light-filled tunnels beneath it.

2. A great deal of heat.

3. A great deal of thermal pollution downstream, in the underground river.

4. A calming effect on the city's population, making them less prone to anger and despair.  It does not suppress happiness or creativity.

5. The suppression of the Egg's latent psychic powers.

The Retrievers

Kashtan Larksmith manages the retreivers, who are an artificially created race of human-Egg. They resemble winged women with eyeless squids for heads.  (They can see, despite appearances.)  They are empaths and psychics.  There are six of them.

They are used to hunt down threats to Drume, typically criminals.  Once captured, the retriever will immobilize her prey, stretch her mouth over the victim's entire head, and neatly bite their head off.  This is made possible by a boneless jaw and a radula similar to a wire saw.

Swallowed heads are diverted to a second stomach, where they are kept alive and fully conscious until they can be delivered to the Egg.

To prevent injury to themselves, retrievers are instructed to break the jaws of their victims before decapitating them.

Each retriever is different.  Duvadembra refuses to kill anyone.  Yoctalys is defiant, and considers the Egg to be her true father.  When Ovia catches a criminal, she punishes them with their own crime before killing them.  Zenziss despises her body, and wishes to be human.  Ulmara and Japherine play musical instruments and are probably in love with each other.

The common populace believes that there is only one of them, who they call Lulu.  The Quadrumvirate encourages this farce.

A Comprehensive Guide to Secret Doors

People will draw an 'S' on their dungeon map many times before they start thinking about what makes a good secret door.

Secret doors are an absolute cornerstone of D&D, and yet they don't get as much attention as other common dungeon elements.  I guess they're a little boring (compared to traps and magic swords).

Here's the thing: secret doors are an excellent opportunity for OSR-style gameplay.  A secret door is a common dungeoneering problem that is usually solved through observation and intuitive solutions (as opposed to system mastery, or having silver weapons).

Sidenote: Courtney has written a couple of good posts but I wanted to write my own.  

Tip #1 - If it's essential, don't put it behind a secret door.

Sort of general disclaimer: if finishing a dungeon requires the PCs to go past a door, don't make it a secret door.  The reward behind a secret door should be optional.  This avoids frustration and allows secret doors to perform their primary function: rewarding players for skillful dungeoneering.

(The secondary function of a secret door is to be cool as fuck; don't underestimate the impact when the wall of the cramped cellar swings away to reveal a forest of glowing fungi.)

by Peter Mullen

Obvious Door, Hidden Lever

These is my preferred archetype.  There's three parts to this.

The Door: A sealed door makes the PCs suspect a trigger is nearby.

The Trigger: They search the room to find the trigger.  

The Reward: They are rewarded for opening the door.

The Door is obvious.  It might be a huge metal door with no way to open it except to discover the mechanism.  It could be a stout wooden trap door that can be smashed (at the cost of noise and time).  It might be a wall of flame that they can jump through at the cost of damaging themselves.

An obvious door allows the players to focus their search here.  Instead of searching every nook and cranny of the whole dungeon, obvious cues like this allow the players to focus their time and attention on key places.  

The Trigger is hidden.  This is the part that tests the players.  They can deduce the trigger from clues, figure out comprehensive ways to search the room, or discover some way to interact with it.  This is the fun part, because this is the challenge.  In the dungeon, this is where the gameplay is.  (One of many.)

Remember that the trigger doesn't have to be super-hidden.  Simple triggers can hide modest rewards.  That's also fun.

The Reward can be:

• Loot.
• A shortcut to deeper levels.
• An ambush opportunity.
• A place to spy on the orcs.
• A way to slip inside the statue so you can shout at the cultists and impersonate their god.

Hidden Door, Hidden Lever

I don't like these as much.  

To be sure, they have both precedent and placement reasons, but they're easier to miss since the players are more likely to walk past them.  

True, you can train you players that you have lots of hidden doors in your dungeons, but then you are also training them to spend their time fully investigating every room in the dungeon.  I'd rather train my players to investigate the things that seem interesting (since they often are more interesting).  We can cover more dungeon that way, and I spend less time saying "you don't find anything".

Hidden Door, Obvious Lever

I guess these exist?  You pull a lever, hear a grinding sound, and then you have to backtrack to find where the door opened.

These are only fun if you have a good wandering monster table, you want to show players have rooms have changed since they were last visited, or time is one of the fun challenges in this dungeon (e.g. the dungeon is literally sinking in the ocean, do we really have time to backtrack).

Meh.

Semi-hidden Doors

There is an opportunity here to make it a two-step process, with doors that are semi-hidden and then triggers that are more hidden.  It's also a gradient--you can have a semi-hidden door with a semi-hidden trigger.

Heck, you can even have a semi-hidden door with no trigger (i.e. push to open).  These are also good.

Semi-hidden doors are defined as ones where the DM uses cues (breadcrumbs) to lead the PCs to discovery of the hidden door, or at least to get them to suspect its existence (so they'll know to search the room).  

Cues for a Semi-Hidden Door (roll a d10 or a d12)

1. Scuff marks or footprints.
2. Hollow sounds as you walk across it.
3. Old stains, or fresh blood dripping through the seams.
4. Breezes.
5. Sounds.
6. Smells.
7. Temperature changes.
8. Anomalous architecture (e.g. discolored stone, sagging walls).
9. A dead end in a hallway (especially if the hallway seems well-traveled).
10. Obviously passable surfaces: waterfalls, curtains.
11. Seeing a creature flee into a seemingly dead-end room.
12. Put a clue on a map.

Using Maps to Indicate Secret Doors

Remember, the whole point of having obvious doors is so players know to concentrate their attention in a specific area.  The clue doesn't have to come from the room itself.  It can come from the mouth of an NPC

Sometimes the clue comes from the map.  OSR dungeoneering is full of shit like this, which is why you'll see so many people making these meticulous maps (as opposed to a quick diagram of which rooms connected by lines).  Examples:

• Symmetry implies a room. (e.g. the lower floor seems to share a floorplan, yet this room lacks a counterpart on this floor.)
• The shape of the adjacent rooms (and exterior wall?) imply that a room should be here.
• Necessity: if you know the tower has 5 floors, then you know there must be a way up from the fourth floor.

Triggers (d20)

Remember that a trigger might just unlock a door, not necessarily open it automatically.  The trigger might also need to be held (if you want to be a dick).

A lot of these options aren't necessarily exclusive.  You could combine some of them into better triggers.

Obscured By Object

1. Recessed lever behind painting.

2. Switch beneath rug or behind tapestry.

Challenging Environment

Some of these can get into puzzle territory.  Good.

3. Hidden underneath really heavy statue.

3.1 A pressure plate is only depressed when a really heavy statue is placed on it.  The statue may be in a different room.

4. Trigger located beneath the surface of the boiling mud.

Integrated into Object

5. The door unlocks when the statue is rotated to point at the door.

6. The trigger is in the hinges of a different door.  When the first door is fully closed, the secret door unlocks.

7. Pull the torch sconce, ya turkey.

Instructional/Riddle

8. The offering bowl is full of ancient blood stains.  Fill the bowl with blood.

9. The mural shows dancers at a festival.  Imitate their dance.

10. The plinth reads "ten men's length, ten men's strength.  Ten men can't break it, a child can carry it."  Place a rope on the plint.

Simultaneous Triggers

11. Both discolored bricks must be pushed simultaneously for the door to open.

Trial-and-Error

This covers situations where there are multiple things to try, and the players just have to guess which one is the correct one until they figure it out.  And because there has to be a cost for wrong answers, pulling the wrong lever usually results in a trap being set off.

Sometimes there's a pattern or a clue that allows intelligent players to deduce which lever is the correct one.  In this case, pulling all the levers is just the (costly) brute-force solution.

If there's no clues to which is the correct lever, then the puzzle becomes: how do we protect ourselves from whatever trap is going to trigger when we pull the wrong lever?  (Hint: use a 10' pole.)

This is actually getting away from strict secret doors and into the trap/puzzle spectrum.

12. Three levers.  The first causes acid to fall from an (obviously discolored) crack in the ceiling.  The second is electrified.  And the third opens the door.

Symmetry

One of the common types of Zelda puzzles.

13. The room contains a lit torch and an unlit torch.  The door unlocks when both torches are lit.

14. The room contains a dozen levers, arranged at different heights.  The door unlocks when all of the levers are set to the 'up' position.

Brute Force

This covers kinds of switches where the biggest limit is how much time the PCs are willing to use.  At worst, this can be pixel bitching.  At best, this is a resource-management choice.

DM: It'll take you 90 in-game minutes to attempt all the combinations.  Do you still want to do it?

Player: Yeah, sure.  Go ahead, roll your wandering monster checks.

And in this case, finding the trigger is only as fun as making the cost-benefit analysis of cost vs. reward.  

Like the trial-and-error triggers, this can be an acceptable brute force solution for puzzles where the players didn't find the clue.

Example. The door will not open unless the correct demon's name is spoken.  The walls are covered with the names of thousands of demons, including the correct one.

Anomalous Architecture

These are basically solved by noticing that something is out-of-place and then interacting with it.  If a player says "I inspect the X closely; tell me more about it" they're 90% of the way there.

15. One of the bricks is a different color than the others.  Push it.

16. A small hole in the wall is revealed to be very deep.  The trigger is 5' deep in the hole, and must be activated with a pole or spear shaft.

17. Investigation reveals that the chandelier chain goes into the ceiling.  Pull the chandelier.

18. Outside the castle window, a small bullseye can be seen on one of the exterior bricks.  Hit it with an arrow.

Repetition

19. One of the bricks is a different color than the others.  Push it three times in a row.

False Backs / Nested

20. The first secret door reveals a small chamber full of garbage.  If the garbage is cleared away, one of the bricks can be seen to jut from the wall.  Pushing this brick opens the second, actual secret door.

21. The cabinet has a false back.  The false back can only be opened when the cabinet is closed.

Deductive

There's also cases where a party might realize late in a dungeon, based on some new evidence, that they might have missed a secret area early in the dungeon.

For example, they might see multiple blue tiles throughout the dungeon.  Later one, they see where a blue tile has been smashed and an empty cavity revealed.  Now they can go back, smash all the blue tiles they saw earlier, and grab the small treasures inside.

(I'm not really sure how to code this one, and since it relies on dungeon design, it doesn't really belong on a "d20 secret doors" generator.

by Peter Mullen

Bad Secret Doors

Just Checks

Roll a Perception Check.  Roll a Search Check.  Roll a Disable Devices Check.

If this is all you are doing, then you are only challenging the character sheet, not the player.  This is boring.

Pixel Bitching

Basically, when the player spends a lot of time doing a boring task to track down some trigger, with no clues to lead you to it.

Here's a bunch of identical tiles.  Roll for each one.

Here's a room full of boring things to investigate.  Spend time describing to me how you're going to investigate each one.

At best, this is a Brute Force trigger (see above).  

Tip #2 - When you expect players to be searching a room carefully, choose carefully how many interesting features you want to put in that room.

I try to limit myself to no more than 2 or 3 significant things in each room.  

Sometimes a room has lots of objects in it by requirement, e.g. a kitchen.  Be careful hiding triggers in kitchens.  The players will remove every drawer and break the sink before they notice the switch at the back of the oven.

Searching  dense room isn't necessarily bad--and it may even be fun if the kitchen is interesting--but it does take time.  Just be mindful of it.

Compare that to a room that is empty except for two discolored bricks and an obvious secret door.  The players will come in, and one of two things will happen.

(a) They'll figure out that they need to push both bricks simultaneously.

(b) They won't figure it out, and they'll move on to the next room.

Either way, it probably won't take as long as the kitchen scenario.  And if they think of the solution later in the dungeon, they can always come back.

Final Note

Spend a moment to think about what is behind the secret door.  A party is usually pretty invested in finding the trigger for a secret door (it's an activity anyone can participate in), so when the door finally swings open, you'll probably have their attention.

Lastly, the reward doesn't have to be treasure.  It can be something bad, like a bunch of zombies.  Zombies are their own reward.

If you still want some more secret door stuff, here's a couple more other sites.

Raging Swan

Dragon's Flagon

Some Traps

Chris wrote up a list of some traps that don't suck.  I'm going to write some more, since that seems like a good thing to make a list of.

What makes a good trap?  

It should follow good OSR principles (similar to the obstacles post I wrote way back).

• No obvious solution.
• Multiple possible solutions.
• Solution depends on common sense (rather than system mastery).
• No specific tool required (no McGuffin, no singular spell, etc).

What is a trap?

A trap can be obvious, such as an open pit.  With obvious traps, the puzzle becomes how to best get across the trap.  Traps don't have to be difficult.  Easy traps can be fun, too.  AND easy traps can become weapons that you later use against monsters in the dungeon.

Obvious traps are probably the hardest to write, and the most fun.  They kind of blur the line between obstacle, puzzle, and trap.  An obvious trap needs to have (a) a reason to engage, (b) a visible mechanism, and optionally (c) an explicit risk.

A trap can be surprising, like a subtle pressure plate.  With subtle traps (where the PC is likely to stumble into it) make sure that you give the player a chance to react before the trap goes off.  We want to give the players interesting choices to make, not just tax their HP.

A boulder rolling towards you is good.  You still have options.  Compared to. . .

A subtle pit trap in a random location sucks.  It sucks because the "solution" to them is to spend your time tapping on the floor with a pole, or pouring out water and seeing if it seeps between the stones.  (I know there is a whole branch of old-school play that enjoys this style of play, but it's never appealed to me, since I believe that there are more interesting ways to challenge players.)

Where should subtle traps be hidden?

Please don't hide them willy-nilly.  Putting a pit trap in the middle of a well-traveled corridor threatens verisimilitude (since aren't orc patrols passing over it every thirty minutes?)

Place traps in logical places.  A kitchen cabinet is probably not going to be trapped, but the chest in the shaman's room probably is.  

If you are going to hide damaging traps, try to build up to them.  Telegraph the possibility before the traps appear.  Before you have complicated double pit traps and slides, it's good to have a room with a small pit trap (to inform players that hidden pit traps exist here).  Or better yet, a room with a broken (exposed) pit trap.

You don't have to telegraph the danger, just the mechanism.  

For example: a lever might open a hole in the ceiling, dumping spiders down onto whoever is below.  A smart party will pull the lever with a rope lasso from 20' away.

This is a good trap.  A player who dies from spider bites will (hopefully) sigh and say "I guess I deserved that.".  

That's what you want from a trap.

Some Traps

Not all of these are technically traps.  Some are just interesting dungeon features.

Horrible Hallways

1. Wall of fire.
2. Zone of unconsciousness.
3. Climb a diagonal shaft, rotating.
4. Crush hallway.  Find a way to survive the crush, or at least move really, really quickly.
5. Portcullis that slams shut to split the party.  You can reunite 1-2 rooms away (don't split the party for too long).
6. Obvious pit trap.  The correct path is hidden at the bottom of the pit.
7. Insanely hot hallway (or room where you have to perform some activity).  Anyone trying to sprint through it unprotected is probably going to burn their feet and die.  Things that reduce damage: being soaking wet, air circulation, walking/standing on soggy leather.
8. Subtle pressure plate.  The trap triggers when weight is taken off the plate.
9. As above, except there are several pressure plates in a row.
10. Goblin barricade staffed by several bow-wielding goblins.

Wretched Rooms

1. Obvious trigger: taking the sword off the pedestal.  Two copper spears shoot out of the wall, impaling an incautious explorer.  A round later, lightning begins to arc between the spears.  A round later, the room begins to fill with water.
2. Poisonous gas seeps from a crack in the wall.
3. Lake of acid.  Get to the island.
4. A dripping wet door.  Opening it floods the room with ancient, rancid water and 3 zombie sharks.
5. Lock that can only be opened at a certain minute each day.  Adjacent, a lock that can only be opened at a certain minute each week.  Adjacent, a lock that can only be opened at a certain minute each year.
6. Archway.  Anyone who passes through it is transposed with a ghoul in a nearby room.
7. Climb a frictionless wall.  (Have fun collecting large furniture.  Shitty tables are treasure now.)
8. The floor of this room is laminated with symbols of disintegration.  If a symbol is touched, all non-stone material in the room will take 3d6 Con damage each turn.  In the room, an (unsupported) pedestal with a stone McGuffin on top.  In the ceiling: spiders and spiderwebs.
9. Everything appears distorted in the mirror.  Humans appear to be orcs, swords appear to be hammers, etc.  The trick is to notice that the pen appears to be a key, and the mouse skull appears to be lock.  Inserting one into the other will cause the door to open.
10. Huge wooden bowl, lined with thin, insoluble gold foil.  Filled with horrible, fuming acid.

Obnoxious obstacles

1. The magic stein can only be carried by someone who is colossally, totally drunk.  They have to carry themselves--no one else can help them.
2. Carry a baby out of the dungeon.  No, carry ten babies.
3. When the lid of the sarcophagus is placed back on top, the bottom of the sarcophagus opens.
4. Sign says "teleporter" but it's really just a big blender.
5. The dragon is sleeping!  Steal things quietly.  (Common sense: it's quieter to carry a chest away than it is to open it, a sack of coins is guaranteed to clink, etc).
6. As above, except some goblins just showed up.  They want to kill you quietly, but if the dragon wakes up, you're all probably going to die.
7. Crossing an underwater lagoon.  Hope you brought a canoe.  Of course something attacks during the crossing.  A fast boat can escape it, a floating table is easily capsized.
8. Functional teleport brings organic material to one place, and inorganic material to another.  Allow teleported people to communicate this (possibly by shouting, roll for random encounter) so they can make a more informed decision.  An incipient threat hastens plans.
9. The door can only be opened in your dreams.  If you open it in your dreams, you can pass through it in real life.  While your body sleeps on the altar, it is inhabited by the spirit of an ancient wizard.
10. Before you can run through them, you need to observe the swinging pendulums to determine their pattern.  Anyone observing the pendulums is hypnotized by them, staggers safely through them, and begins to self-mutilate by dancing in the middle of all of them (1d3 damage per turn).