Boom!
All you need is a bunch of people, small glass
and a bottle of anything alcoholic.
It is about numbers. You can play this game on
any prime number. For example, on 7. The one who
starts says 1, the person beside him says 2, and
so onin a circular way. When someone has to say
number 7, or a number that is divisible by 7 or
contains digit 7, he have to say Boom! and the
circle turns. Who mistakes, drinks, and starts
a new round.
It gets really interesting after 5 or 6 rounds.