You will need a glass that you usually fill about a third of the way with beer(but you can put whatever amount you want). You should have at least 3 players.
Everyone gathers around the glass and puts one finger on the edge. The first person will start and count "1,2,3..." after that they are going to say a number that is between 0 and however many players there are. When the person says that last number everyone at the table either chooses to keep their finger on the glass or lift it up quickly. The player is trying to guess how many fingers will be left on the cup. The numbers need to be counted at a fast pace so that there is no confusion if someone picks their finger up faster or slower than someone else. If player #1 gets the number right then they are out and will not be drinking the beer in the glass. Then the next person to the left goes and so on. The last person to be left without having a correct guess has to chug the beer in the cup. This game goes by very quickly.