I'm going to wait until you find a programmer and decide things such as genre and theme before I make up my mind about it. Generally, I like the idea of doing something I like, cooperating with people I like and getting money after I finish. Things I can do are pixel art, beta testing (I'm one of the best SP players around which might come in useful), level design and design of some other game-related stuff. Note that I'm fully useless in creation of 3D games though. Also, if you don't find a serious programmer who's willing to help, I'm really awesome at GML, but then again, it's just GML.