Each team fills each cup to a predeterminded level, typically four or six ounces. This will require either four or six beers per game.
The game is played with the same number of ping pong balls as there are players per team, either one or two. Each team is allowed to throw their ping pong ball(s) unimpeded into the other team's cups, one at a time. If the ball goes into a cup, the other team must consume that cup of beer and remove the cup. If the ball does not go directly into a cup, the defending team is allowed to obstruct the ball from entering a cup, either by swatting it or by blowing it away.
The game is won when one team clears their opponents cups. The losing team must immediately drink the winning team's remaining beer.