Facepainting party. Get a few artistically inclined friends to sit at the entrance and paint folks before they enter! This one would produce fantastic photos, no booth necessary - just ask each guest to think of their favorite movie/kid's book/etc in advance!
Facepainting iPhone and iPad app by JS900. Genre: Entertainment application. Price: $4.99. http://click.linksynergy.com/fs-bin/stat?id=gtf1QuAg8bk=146261=3=0=1826_PARM1=http%3A%2F%2Fitunes.apple.com%2Fapp%2Ffacepainting%2Fid380469350%3Fuo%3D5%26partnerId%3D30