Either caps, where you grab two oversized cups (like the ones you get at ball games) and set them about 10-15 ft apart. Two people to each cup, take turns shooting quarters or caps into the opposite cup a la beer pong. If one team makes it, the other has a chance to rebuttal. If they don't, they chug. This game's good when there's only a few drinking.

Then there's "Ride the Bus". You make a pyramid of cards starting with a 5 card row. Then you pass out the remaining cards. The dealer methodically goes row by row flipping over the cards. If you (the player) have that type of card in your hand, you place it on the flipped card. (i.e. a jack is flipped; no matter the color or suit, you place your jack down). After the whole pyramid is done, the person with the most cards left must "ride the bus". Basically, you set up another pyramid. The person "riding" must flip one card over per tier of the pyramid. If the card is a face card, they must drink, and replace all the cards they have chosen so far. They start at the bottom once again and work their way to the top. Hilarity ensues when after a rough bottom few tiers, they reach the top only to find a face card in the apex.

Also this game gets you really really drunk.