This question largely pertains to basketball and American football. I've seen footage from the team locker rooms during halftime where the coaches and players go over issues from the first half that need to be addressed, key statistics, etc.
I've often wondered what the referees do during the halftime break (other than get a breather). Do they go over replays where they botched calls? If so, do they have someone whose job it is to create the "highlight reel" of missed calls, e.g. a coach for the referees?