Game rules

Preparation: Divide 4 or more people into two teams, each team has the same number of people; each person has a light plastic cup with the same amount of drink in the cup. The two teams stand side by side on either side of the table.

After the first person in the two teams clinks their glasses or listens to the command, they finish their drinks at the same time.
Put the empty cup squarely on the edge of the table, with the bottom of the cup hanging slightly in the air; use only one hand to flick the bottom of the cup to flip it over and place it upside down on the table.
If unsuccessful, you can try again as many times as you like. Only after the cup is stably inverted can the next teammate start drinking.
The first team to complete "drink and flip the cup" as a whole team wins. In the event of a false start, the player must refill the same portion and do it again.
You can switch positions or adjust the portion size of each cup in the next game, but the two teams must be the same.

Two-person version: Each person ranks the same number of cups and completes each of their cups in order. The first person to complete the cup wins.