21 will prove if everyone in the group has a good memory.

1. The player with the device will start by saying «1»​ unless number 1 has a rule.

2. The player to their left then continues to say «2» and so on in the circle of players.

3. At the start of the game, the players will add three rules to three numbers. The rules are meant to be things to say or do instead of saying the number. So let’s say we add «say horse» to the number «7». Each time a player is meant to say 7 they will have to say «horse» instead.

4. Each time a player forgets about a rule, the player with the device presses the «wrong» button to reset the count and everyone takes a sip.

5. The player that forgot about the rule will then be handed the device and start the next round.

6. The player with the device will press «next» each time someone says a number or rule during the count to control that all rules are being remembered.

7. Each time the players count all the way through 21 they will add another rule.

8. The group wins by going through a full round of rules.