KEEPER: What is the air-speed velocity of an unladen swallow?
ARTHUR: What do you mean? An African or European swallow?

KEEPER:In order to maintain air speed velocity...
a swallow needs to beat its wings 43 times every second.

http://www.rit.edu/~smo4215/monty.htm#Scene%2023

KEEPER: What is the air-speed velocity of an unladen swallow?
ARTHUR: What do you mean? An African or European swallow?
KEEPER: What? I...I don't know that! Auuuuuuuugh!
BEDEVERE: How do know so much about swallows?
ARTHUR: Well, you have to know these things when you're a king
you know.