Scatter hoops of varying sizes around the hall or gym.  Call out an instruction for travelling around the hoops (not going in them yet though). When you call out a number that is how many children must get into each hoop. 

For classes reluctant to work with children of opposite sex you can call out 'a boy and girl' and they must get into a hoop. Children must not push other children out of the hoop even if they have too many. Also all parts of body must be in hoop - no toes over edge.

If too many or not enough children in hoop all those involved are out.

Fiona added a comment to this idea:

"I use this game to get a number of children in a hoop. When the hoop has the required number of children they pull the hoop up to waist height and this saves anyone else cheating and trying to get in the hoop. This works really well!"