The Harmony Sweepstakes

A cappella singing, that distinctive style usually performed without instruments, has roots going back centuries. But it seems to be making a comeback. This fall, NBC will premiere "The Sing Off," an a cappella American Idol-type competition. Two feature films about a cappella are also in the works. The only nationwide post-college a cappella championship in the U.S. is held in the Marin County city of San Rafael. We stop by The Harmony Sweepstakes' recent 2009 finals competition.