I’m far from the first person on the net to link to AIM Fight. It gives you a score based on how many people are online that have you in their buddy list, and how many online people have them in their buddy lists, out to three levels.
If you are in the top 5%, you get a ranking as well as a score.
It’s a fun little diversion (and yes, my primary screenname is in the top 5%, ranked 39306, at the moment).