It needs to be line art (one color) so that it can be embroidered or stenciled onto things. Creative color is fine, but just one solid color.
It needs to be trademarkable (not easily confused with another video game company logo). Our trademark attorney may have a say in picking the winner from the finalists, so do a tiny bit of research on the web before you give us the Activision logo in a different color. We want you to win!
It has to contain our name, "GivePlay"
We need to know what fonts you use, if you use any. You could draw the letters yourself, of course. If you were truly hardcore you could make your own graphics tablet from parts and then use that to draw the letters.
The logo you create for us needs to be your own work, unencumbered and royalty free--if you win, you must be able to grant us full and exclusive rights to use it forever. No cribbing!
For the finished product we need a hi-res PSD or (even better) Adobe Illustrator File. But who doesn't?