Mega-movie star and director George Clooney will be joining a long list of Hollywood stars in the "Stand Up to Cancer" (SU2C) telethon, airing on Sept. 10, 2010 at 8 p.m. ET. In a powerful effort to raise funds for cancer research, the event will be featured on a number of network channels. Clooney is one of dozens of celebrity participants and performers in the event. (Jason Merritt/Getty Images)