Show a project using a 3-D component designed on a computer, and win a 3D printer. Kind of catch-22, since having a 3D printer will go a long way toward winning this.

http://www.instructables.com/contest/makeitreal/

or... perhaps my temp controller for the food challenge

http://www.instructables.com/contest/foodscience/

I think it has potential... but it turned out that I need to do some work on sealing up my smoker to get it to be truly controllable by air-flow. It is partially controlled by fuel load as it is now... leaky.