Biggus Dickus - Monty Python, Life of Brian.

 From what all I've heard, the Pythons didn't tell the extras playing the centurions about Palins' affected lisp or the whole "Biggus Dickus" bit. They just told them not to laugh. The look of fear on the guy on the right when Palin mentions his wife is the funniest part of this.

How England used to vote

The Treaty of Westphalia