The Orc and the Pie is a very brief Adventure Module by Monte Cook, playable in just about any role-playing game system imaginable. It's an example of the simplest possible, yet technically complete adventure.

Adventure Background: An orc has a pie.
Adventure Synopsis: The PCs kill the orc and take his pie.
Adventure Hook: The PCs are hungry for pie.

Seems to be gone from Monte Cook's website, but it's still available on GitHub, among other places.

Tropes used in The Orc and the Pie include:
  • MacGuffin: The pie
  • Minimalism: A one-page, one encounter adventure that still has everything you need: a monster, a 10x10 room, treasure, and a future adventure hook ("Somewhere, there is a bakery making these good pies. Perhaps it's guarded by more orcs.")
  • Mook: By implication, the orc.
  • Our Orcs Are Different: This one happens to have a pie
  • Pastiche: Of every adventure module ever written, but especially of Dungeons and Dragons.
  • Short Story: But it's very easy to make it part of any longer story.