I’ll try to keep this up-to-date as I find more sites. Feel free to comment and add more.
VGMusic – really well-done imitation of some warez sites that were closed down.
Homestar Runner – Nobody! Nobody! It’s the King of Town!
Penny Arcade and PvP switched artists.
Fark – Farked by guinea pigs!
Something Awful – HOT BORING FETISH ACTION!
Lizard – Lizard goes all explodey.
Real Life – Dean’s doing horribly in the humor department, but here’s some sort of “what’s the difference” strip.