For my project, I posted an unfinished drawing on an art website. I drew an image of a cartoon character that looks as though she is falling or slipping on something. Other users were asked to finish the drawing in any way they please and post the image on the website. The main purpose behind this is to see what different people will add to the same image. People can add their own background, word balloons and even other characters. They could do whatever they wanted to the image as long as they did not stretch or squash it. I tried to be a general as possible when explaining the rules because I didn't want to lead any participants into a certain drawings.
I had hoped that the unfinished drawing would encourage creativity, but so far not too many people have responded no matter how I advertised. I could just turn the entire project into a contest to generate more interest. The prize could be the on site currency that is quite popular. First prize would be 500pts, second prize could be 300pts and third prize could be 200pts. If that fails to gain attention, I'll probably need a second plan.