In two-player mode, after your opponent fouls in US pool, grab the cue ball and before you take your shot, push it in between two other balls that are close together on the table, so that the cue ball touches both of the other balls. This nudges the balls a bit and if they are in the right place, you could set yourself up a treat, or ruin your friend's plans. The computer players don't mind, but your friend will.