One of my friends has a theory that the USA were no good at proper sports, so they invented their own. They were no good Rugby, so they gave everyone huge pads, a helmet and stopped the game everytime someone dropped the ball, and called it American Football (or football). They were no good at Hockey, so again, they gave everyone huge pads, a helmet and stuck them all on ice. Genius.
Sadly, the USA have either overtaken everyone at all sports, or they're catching up quickly.
Polymath, I believe the World Series is called so because it was named after a newspaper. I read that somewhere, it might be wrong.