The players sit in a circle, preferably at a table, each with a full cup of beer. One person is chosen as the dealer. The dealer deals four cards to each player, the first two face down and the second two face up. Each player then places his/her cards in a 2x2 tableau, like so: (X=face down, O=face up)
O O X X
Each player then takes a look at their two face down cards and places them back on the table, face down in either order. The object of the game is to get the lowest score, hence the name golf. Scoring goes as follows:
The players mentally add up their scores. Play then starts with the player directly to the right of the dealer. Player 1 picks up the top card from the remaining stack. After seeing its value, he/she can decide to either discard it or exchange it for any of his/her existing cards. If he/she chooses to discard it, he/she simply places it face up in a pile next to the deck and play continues to the next person. However, if the card is of lower value than any of his/her existing cards, he/she can exchange the lower-valued card with it. If he/she decides to replace a face-up card, the chosen card is put in its place, placing the old card on the discard pile. However, if the player chooses to replace a face-down card, the replacement card is placed face down in its place, putting the old card on the discard pile. Play then moves on to the next player.
At any time during a player's turn, be the lowest. After that, every other player gets one more turn. Once every player has had their final turn, scores are mentally calculated and all cards are then shown. If the person who knocked indeed has the lowest score, then everyone in the group must drink the difference between their score and the lowest score. If the person who knocked does NOT have the lowest score, then it is said that he/she has been 'sent to the clubhouse', lowest score. Regardless, whoever has the lowest score is the only one who does not have to drink.
Remember that the face-down cards can only be looked at once, at the beginning of the game. Every extra time a player must check his face-down cards to see what he/she has, the penalty is a drink. Which is hardly a penalty, when you consider that, if you accidentally replace a face card with say a ten, you're shit out of luck. The buzz factor is potentially high for this game because it is not out of the question for someone to have been dealt with three face cards and a two right off the bat. If they are a real bastard, they'll knock right away, leaving the others stuck with scores in the twenties, which is a lot of beer to drink. The philosophy here is to be nice… because you might be next.