Kids are paired off and have to walk around in a squatting position with both hands on their ankles.
They need to attempt to bump each other over.
You lose if you
Let go of either of your ankles
You can have several rounds with winners playing winners and losers playing losers.
You could have a free-for-all competition with only one winner.
You could divide the group into two teams or four packs and have them attempt to co-operate as a group.