Double Fine's upcoming Roguelike, RAD, has a competition running to have your graffiti artwork featured in the game.
You could also win a RAD Skateboard, a RAD Lunchbox, a RAD Floppy Disk, a RAD Action Figure, and Digitally RAD Copy of the Game, provided you live in the USA and submit your entry by the end of June.
Why not give it a shot? Submit your RAD artwork here
(Question: Will it ever get tiresome saying RAD all the time? Answer: Yes.)