Sadly, I only found out about the Where The Wild Things Ought to Be contest after the winner was picked. Sponsored by We Love You So, the official blog of the Spike Jonze film adaptation of Where The Wild Things Are, intrepid Photoshoppers were invited to wild up the scene, artwork, or video clip of their choice. Winners received a set of custom Wild Things skateboard decks, so it wasn't a huge surprise that the grand prize winner was a skate-themed animation. But all the posted entries were really fun (make sure to click through the tiny thumbnails).
(Speaking of Photoshop contests, this one from 1000words.com is particularly groovy.)