It's every man or woman for themselves. You'll need a referee to watch over the game. What happens is, you start out with however many people you'd like. To start the game, all participants raise their cups of beer and exclaim "Everybody drinks, everybody wins!!!"
The referee gives the call and everybody drinks and then tries to flip their empty cup off the edge of the table so that it lands upside down. After each participant completes their flip they raise their arm and yell "Done!". The last two people to finish their flip are eliminated.
Keep playing and eliminating people until there is a champion. Make sure when your champ wins that you give them a nice clear path to the toilet cause the beer will be up in no time! The champion can be called "Captain" until he/she is overthrown as champ.