Equipment needed: None
Try to count to 13 by counting one by one. The first person says «One», the second says «Two» etc. When you get to 13, the person that finishes the round gets to make a new rule.
This rule could be anything. You could, for instance, decide that «Two» should be «Meow», or that «Five» is now «Cheers!» and drinking a sip. A new rule is made for each round. The game could after a while look like this:
«One», «Meow», «Three», «Four», «Cheers!» and drink, «Six», «Two», «Eight», «Nine», Stand up and say «Hola!», «Eleven», «Twelve», «Thirteen» – and a new rule is made.
If someone forgets a rule or fails, they have to drink. The next person then starts from the beginning.