Ron Palillo, best known as goofball student Arnold Horshack on the '70s sitcom "Welcome Back, Kotter," died August 14 of a heart attack. Palillo also guest starred on "The Love Boat" and "CHiPs," did extensive voice work on animated TV series, and, at the time of his death, was teaching acting in the Palm Beach area. He was 63 years old.
TV Stars We've Lost in 2012
A look back at some of the television greats who have left us this year.