If your serve touches the net, you must serve again. If it touches the net and lands on the floor or bounces back to your side of the table, you lose a point. Each side serves alternately every 2 points.The player or doubles team that first scores 11 points wins the game. [I've always played to 21, alternating serves every 5 points.] However, you must win by 2 points, so there is theoretically no upper limit that scores may reach (unless the Expedite rule is invoked -- See link below). A return (but not a serve) may touch the net as long as it goes over. You lose the point if - your return goes into the net; - your return goes over the net but misses the table; - the ball bounces more than once on your side of the table; - you hit the ball before it bounces once on your side; - you otherwise fail to return your opponent's shot; - you move the table; - you touch the table with your free hand; - you touch the net. The ball may hit the edge of your opponent's field but not the side of the table. It is legal to hit the ball around the side of or under the net (that is, off the table) to land the ball on your opponent's side. See more rules and details at http://www.usatt.org/rules/index.shtml, especially section 10.