If you like winning stuff, you might want to check out BlizzCon and its contests. Whether or not you'll be going to the sold-out event this October, there's something for you to participate in. Obviously, if you're not going, you won't be able to join staples like the costume contest or the impressive (and often hilarious) dance contest, but most of the BlizzCon contests can be joined online.
If you think you've got the chops for stuff like making movies, ace graphic design skills to make motivational posters, or even songwriting skills and making dioramas, then head over to the BlizzCon contest page and read about how to submit your entries. Unfortunately, if you think you're a funny guy (or gal), Blizzard wants to see you in person.