If you've ever played badminton, you know that the thing you hit, called a shuttlecock, never goes as fast as you want it to. No matter how hard you hit it, it always slows down to a boring speed incapable of causing any destruction whatsoever. That is, unless you're Korean Olympic badminton gold me...

Filed under: Marketing and advertising, Business of sports, Entrepreneurs This post is part of our feature on Money Winners of 2008 . See all 20. It wasn't like Michael Phelps hadn't done well for himself by the time he got into the swimming pool at the 2008 Beijing Olympics. He was pulling in betwe...