XKCD, the great nerdy comic strip, is in fine form today, with a danceable twist on "Talkin' 'Bout My Generation."
See also:
Where LOLCats come from
Geeky comic strip uses Cory as the punchline
Funny map of online communities in the style of a D&D map
Nerd humor about Katamari Damacy
Ironic Internet malapropism grid
Geeky comic about chess and roller-coasters
Sarcastic comic about computational linguistics (and emo kids)
Pi joke