Table tennis, also known as ping pong, is a sport in which two or four players hit a lightweight ball back and forth across a table using a small paddle. The game takes place on a hard table divided by a net. Except for the initial serve, the rules are generally as follows: Players must allow a ball played toward them to bounce one time on their side of the table, and must return it so that it bounces on the opposite side at least once. Points are scored when a player fails to return the ball within the rules. Play is fast and demands quick reactions.