http://notorc.blogspot.com/2007/09/anatomy-of-humor-5-guy-walks-into-bar.html
Many many variations on the old start to a joke. Many are stupid and forced, which disappointed me, although I did learn a couple of new ones.
They left out my favorite, though.
A mushroom walks into a bar and orders a drink. Bartender says, "Get out of here, we don't serve mushrooms."
Mushroom says, "Aw come on, I'm a fungi!"
A friend's wife laughed at that joke, literally, for years. She'd call up and leave messages on the answering machine with it.