Okay, if you don't wanna read that, here's a quick rundown.
• After your team gets 4 fouls in a quarter, the other team gets put into the "bonus". This means that every foul after your fourth foul is 2 free throws for your opponent.
• If a single player on your or your opponent's team gets 6 fouls, he will be fouled out, and be unable to play anymore. In the case that you have less than 5 players available due to fouling out, the empty spot will be replaced by a "Lucky Fan".
• Sometimes, a hard foul will be registered as a "flagrant foul". These fouls count only as 1 foul, but the opposing team gets 2 free throws and possession of the ball, regardless of whether your team is in the "bonus". This is /probably/ the source of most BB injuries.