Not just a pretty face history lesson: Communism, Socialism, Fascism
A great explanation via Ann Landers, without a full blown history lesson:
Socialism: You have two cows. Give one to your neighbor.
Communism: You have two cows. Give both cows to the government, and they may give you some of the milk.
Fascism: You have two cows. You give all the milk to the government, and the government sells it.
Nazism: You have two cows. The government shoots you, and takes both cows.
Anarchism: You have two cows. Keep both of the cows, shoot the government agent and steal another cow.
Capitalism: You have two cows. Sell one cow and buy a bull.
Surrealism: You have two cows. The government makes you take harmonica lessons.