From scene 23 of Monty Python and the Holy Grail
. No one is allowed to cross the bridge
without answering the bridgekeeper's three questions
. Eventually, this bridgekeeper was vanquished by the extraordinary wit
of King Arthur
BRIDGEKEEPER: Hee hee heh. Stop! What... is your name?
ARTHUR: It is 'Arthur', King of the Britons.
BRIDGEKEEPER: What... is your quest?
ARTHUR: To seek the Holy Grail.
BRIDGEKEEPER: What... is the air-speed velocity of an unladen swallow?
ARTHUR: What do you mean? An African or European swallow?
BRIDGEKEEPER: Huh? I-- I don't know that. Auuuuuuuugh!