The zany, unconventional humor of Monty Python beckons to a new generation as PBS rebroadcasts the series that first mugged American funny bones in 1974. The troupe that made Spam and lumberjacks fit subjects for musical tribute and the Ministry of Silly Walks as familiar as the Department of Defense includes, John Cleese, Terry Gilliam, Eric Idle, Terry Jones, Michael Palin, and the late Graham Chapman.