Ron Palillo -- the actor who played Horshack on "Welcome Back, Kotter" -- died this morning at his home near Palm Beach, FL from an apparent heart attack ... this according to someone close to the actor. Aug 14, 2012
"Welcome Back, Kotter" fans are mourning the loss of Ron Palillo, who<a href='http://www.cnn.com/2012/08/14/showbiz/obit-palillo/index.html' target='_blank'> died</a> of a heart attack Tuesday at 63. As Arnold Horshack, one of the "Sweathogs," on the ABC series, Palillo was beloved by viewers for his unique laugh and "Oooh! Oooh!" catchphrase.