A browser-based fantasy basketball game. Users create a basketball player, join teams with others, and compete against other teams. There are different leagues, and divisions within the leagues.
Relatively popular, it's undergone very few changes of late which has led to some discontent amongst the user base.
Worth noting that both of the other definitions were created by ex-members who became disenfranchised once they realized that they weren't the center of the CR universe. Both became very unpopular with other users. One's name actually became synonymous with being a spammer.
Insult delivered to an unpopular spammer on Court Rivals: "Are you Tarheels?"