Everyone mills about until you shout "groups of four!" — then scrambles to huddle in the right size. Fast and silly.

How to run it

1. Have everyone move around the space freely.
2. Call out "groups of ___!" with a number.
3. Players scramble to form groups of exactly that size; anyone left over is out or cheers on.
4. Repeat with different numbers, speeding up each time.

Source & full detail: Teach Starter ↗