Improv Everywhere. Crazy people. Includes The Amazing Stuntmen, Look Up More, Even Better Than The Real Thing, and Cell Phone Symphony. Celebrity Trash is noticeable for the fact a real celebrity got involved, while Aspen made me fall over laughing about halfway down when the "Meet a Black Person" sign came out. Also features many missions on subway trains in New York.
Check out all the missions, but don't blame me if you spend hours here. I just spent an hour & a half myself, and I read quickly.