Divide the players evenly into two teams (this game doesn't work as well when there are an odd number of players). Each players grabs a drink, then the two teams line up side by side.
After a countdown the first player in line on each team starts downing their drink. As soon as the first player finishes their drink, the player behind them in line starts downing their drink. When they finish their drink, the player behind them starts downing their drink, and so on.
The winning team is the team that finishes their drinks first. It's important to remember that a player may only start downing their drink when the player ahead of them in line has finished drinking.
If a player starts drinking early their team is disqualified.