The Tour de France is probably the premier cycling race in the world. It attracts big money and riders from around the world go to France to compete in it. It has recently been mired with scandal due to the fact that the riders have been taking steroids. Lance Armstrong is probably the most famous of the people who were caught.
To be honest, I'm not really a fan. But like Canuckster said, rules are rules, and I'm not going to be the first person to break them.
