He plays one of the most recognizable characters in television history. He was mentored by the great Jim Henson. He has more daytime Emmys than most TV actors accrue in a lifetime. And yet, most days, he walks around the world, completely unrecognized by his fans.  His name is Kevin Clash. But you might know him best as the character he plays on Sesame Street: Elmo. Kevin is the subject of a new documentary called "Being Elmo," which won the Special Jury Prize at Sundance. The film is currently in limited release.  Kevin talks about how he rose up from his humble beginnings to play the most popular furry red monster on television.