'Welcome Back, Kotter' Cast: Where Are They Now?

Ron Palillo, who played Arnold Horshack on "Kotter," died of an apparent heart attack in Florida on Aug. 14, 2012. He was 63. Palillo's character was known for his phrase, "Ooh, ooh! Mr. Kotter!" and his distinct laugh. But the actor failed to find fame when the show went off the air in 1979. He had a few odd roles in movies and television shows, but not solid stardom. (Bobby Bank/Getty Images)