We all know it but thought I'd repeat it.
One softish ball, and lots of children are all that are needed.
Aim: To get the ball and throw it at other players' legs. Once hit they are out.
Rules: Not allowed to move once someone picks up the ball; Can only aim below the waist; If you catch someone's throw they are out; you cannot protect your legs by blocking with arms.
In constant demand with my classes!