A type of humor that is recurisively applied to the humor carrier, be it a joke, a cartoon, or a node. Favorite among the geek crowd for the intellectual effort it sometimes takes to recognize the obscure self-reference in a joke, and the possibility of getting high on ensuing mindfuck. Examples include most of the (rather lame, no offense) writeups in the recursion node, most of the misinformation node, a lot of User Friendly cartoons, and the following (again, rather obvious, but I can't come up with anything better right now) joke:

An Arab, a Jew and an American walk into a bar.
The bartender says...
"What is this, some kind of joke?"