On what TV series did the actor who played Ryan O'Reily on Oz play John Gavin?
Dean Winters:  He is known for his role as Ryan O'Reily on the HBO prison drama "Oz", and has also appeared on such television series as "Rescue Me", "30 Rock", and "", as well as the character "Mayhem" in a series of Allstate Insurance commercials.
i don't know