This dungeon is a dungeon that you run only after all of the PCs have died in the last dungeon you ran. It is also my submission to the 2015 One Page Dungeon Contest.
It is a post-TPK dungeon, where you start in the afterlife with nothing except for your favorite set of clothes and a couple of pennies in your pocket. You will, of course, have a small chance to return to life, but it is a small chance.
Writing it, I think the best thing is that high level parties might just be able to steamroll the dungeon. Kill the angel, bully their way into heaven. Or shake the demon by his collar and force him to resurrect them. Of course high level adventurers can cheat death! They do it all the time. Of course they can sneak into heaven! They are adventurers, after all.
Anyway, you can download the dungeon HERE.
And +Daniel Dean wrote an excellent one-page review of my one page dungeon over HERE. He has a ton of good ideas about how to actually run it. If you want to turn it into a two-page dungeon, just print this out and staple it to the back.
And if you want an unkeyed map for the players, here it is:
I am the best artist, yes.