One of my favourite scenes from Monty Python and the Holy Grail. The Bridge of Death, featuring the Old Man from Scene 24.
Old Man: 'STOP! What is your name?'
Arthur: 'It is Arthur, King of the Britons.'
Old Man: 'What is your quest?'
Arthur: 'To seek the Holy Grail.'
Old Man: 'What, is the air-speed velocity of an unladen swallow?'
Arthur: 'What do you mean, an African or European swallow?'
Old Man: 'I-I don't know that.' WAAAAAAAAAAAAAAAH!
Another one from Holy Grail
Knight: 'We are the Knights who say.....Ni'
Arthur: 'No, not the Knights who say Ni, those who hear it seldom live to tell the tale.'