I have the best drinking game ever. It is extreme to insane drunkeness. 4+ players. This is a Canadian Navy classic.
Lay out six levels of cards in a pyramid shape, face down. Deal out the remainder. One card at a time from the bottom row of the pyramid flip up. If you have the card that is now face up in your hand you MUST play it.
By playing it you give drinks to some one else. Each row of the pyramid is worth more then the previous row. (2-4-8-10-12-14 is a good combo- but you could make it whatever depending on dificulty).
Continue with all cards in each row, one at a time.
You can not split one card between players. However if you have double of the same card then you can get two players. Remember you MUST play when if first comes up or you take double the drinks of the row it's discovered. This is a game of revenge so plan ahead to who you are giving drinks to.
Two rounds of this and I promise one of your friends will pass out on you couch before you go to the bar.