The official site of the Association of Tennis Professionals
The Fédération Internationale de Football Association (French for International Federation of Association Football) i.e. Soccer
Warning: very slow-loading site sometimes.
The official site of the National Football League
The official site of the Professional Golfer's Association
Skateboarding, snowboarding, BMX, skiing and surfing.
This site has the latest news on the U.S. Snowboarding team
The official site of the U.S. Men's and Women's gymnastic teams