Table tennis, also known as ping pong, is a sport in which two or four players hit a lightweight, hollow ball back and forth with rackets or paddles. The game takes place on a hard table divided by a net. Except for the initial serve, players must allow a ball played toward them only one bounce on their side of the table and must return it so that it bounces on the opposite side. This game can be played inside or outside. Points are scored when a player fails to return the ball within the rules.