The 'Life of Brian' Debate (1979)

From Wikipedia:

Shortly after the film was released, Cleese and Palin engaged in a what would become an infamous debate on the BBC2 discussion programme Friday Night, Saturday Morning, in which Malcolm Muggeridge and Mervyn Stockwood, the Bishop of Southwark, put the case against the film. Muggeridge and the Bishop had arrived 15 minutes late to see a screening of the picture prior to the debate, missing the establishing scenes which demonstrated that Brian and Jesus were two different characters, and hence contended that it was a send-up of Christ himself.
Both Pythons later felt that there had been a strange role reversal in the manner of the debate, with two young upstart comedians attempting to make serious, well-researched points, while the establishment figures engaged in cheap jibes and point scoring

See also: Not The Nine O'Clock News: Blasphemy Against Monty Python (Thanks Steve)