Being a big Australian Football League fan, (and Sydney Swans member), I was chuffed when the ultimate AFL application Aussie Rules Live was released. It has pretty much everything you need to follow your team and all the others, including live scores when the games are on.
AFL is a social game, with footy tipping giving you a reason to have a competition between your friends to see who gets through to the top of the ladder. You can extend your network outside of your immediate network to others who are also passionate about sport. It adds another dimension to use a tool such as Twitter to keep in touch with your favourite team for me its @sydneyswans, and your real and online friends live while the game is on.