OpenGameArt.org is currently hosting a pixel art contest. They are looking for hair, faces, clothes, accessories, and other modifications to the base sprite sets they commisioned. The entries don't need to be extensive, just cool. Here are the sprites you'll be working with:
By: Migel Angel Hijo de Pedro
By: Mandi Paugh
Note: These are not the full sprite sets -- they're just previews! The full sets can be found on the contest rules page.
The winner of the contest will receive US $100, with a second prize of US $50 also available. Interested? Stop by and read the rules, then submit an entry!
Go and win some money!