A beer game played at many parties or tournaments. There are at least four people on each of the two teams. They are lined up on each side facing each other, each person having one cup of beer each filled anywhere from 1/4-1/2 full. The "starter" faces his opponent, cheers with him, and chugs a beer. Next he must put his cup right side up on the table with it hanging off the edge just barely. Using your hands or fingers you must flip the cup on its top (half a rotation). After one person has completed the cycle, the next person in line may go. The team that finishes first wins.
There is also a version where the losing team has to vote out one person (survival mode). The remaining of the losing team must pick up the slack and drink the same amount of beer. Alot of people are saying to themselves right now "What happens when there is only one person left?". Trust me, I have beat 4 people by myself. It all depends on how fast you can chug and flip.
The version of Flip Cup that we play here (NCSU and UNC-CH) is what I would like to call a "hardcore relay" version. I am not sure if anybody has ever played this way, because when I come into contact with other Flip Cup players, they play the standard way. The same rules apply as they do in the original version. The exception is everybody has TWO cups instead, filled with the same amount of beer. The person at the end of the table is no longer the "finisher" but yet the "anchorman". The "starter" now becomes the "finisher" also. The game starts as usual, the Starter cheering w/ his opponent, and the relay goes down the line the in the proper order. When it gets to the person at the end of the table opposite of the starter (left/right), that person (Anchorman) will drink and flip both their cups in ONE turn. Then the relay heads back the other way towards the starter/finisher again, ending the game. This version takes twice as long, but will also get you twice as drunk. The emphasis on the Starter/Finisher and the Anchorman is crucial to winning.
The great thing about this game is that is totally opposite of games like beer pong where the winner drinks less. In Flip Cup the people that win are most likely going to be the drunk people, seeing that they finish first. The losers just drink last and occasionally you can get them to do some beer bitch duties such as pour the winning teams beer, let you borrow their beer, or go get your beer for you.