There have been a couple of cases where the NBA has filed successful UDRP complaints against people who had "NBA" in domains (obviously, in cases where it was referring to the NBA, which this one clearly is). As a result, I'd drop it as soon as possible, since they'll probably be not too happy about this one.
Also, you're courting even more danger with the Super Bowl domains. The NFL is even more aggressive about protecting that term, so you're going to run into UDRP hell on that one.