Waitress: (brightly) "Well, there's spam egg sausage and spam, that's not got much spam in it."
Customer: (exasperated) "I don't want ANY spam!"
Eventually, a group of Vikings at the cafe drown out all conversation by chanting more and more loudly the word "Spam".
The sketch was the final sketch of the 25th show of Monty Pythons Flying Circus, and was first aired December 15, 1970. Despite its shortness, the sketch achieved immense popularity.
SPAM was one of the few meats excluded from the British food rationing that began in World War II and continued for a number of years after the war and the British grew heartily tired of it, hence the sketch.
The phenomenon, some years later, of marketers drowning out discourse by flooding Usenet newsgroups and individuals' email addresses with junk advertising messages was named spamming in honour of this sketch.