Cue sports
Pool or pocket billiards, in which the goal is to use the cue ball to knock other balls into "pockets" (holes cut into the rubber cushions, so that the balls can drop down into nets or a collection tray).  There are many different pool games, such as "eight-ball", "nine-ball", "cutthroat" and "killer".  Pool is usually played with either nine or fifteen balls (besides the cue ball).