Kingdom of Loathing is a questing, browser-based role-playing game.
It's full of puns, bad jokes, odd quests (haiku among them), and in-jokes galore.
Surreal, and oh-so-funny. Kind of addicting. Don't let the stick-figure art turn you off of it: it's endearing, and after you play it for a while, you realize that it fits the mood and style of the game perfectly.
If you're having trouble with the game, the wiki for it is here.