Standard game of stuck in the mud
The children move around the room. The child (or children) who is "it", chases them. If a child is "tagged" they must stand still with their arms straight out from their shoulders to the side of them. The other children can free them by running under their arms.
1. Set the stuck child free by crawling through their legs or giving them a high-five
2. Give two children a soft ball/beanbag; play is exactly the same but when you're stuck, being given a ball/beanbag sets you free. Naturally those with the ball/beanbag can't be tagged ensuring that at least two children remain free at all times. This also means you can nominate two or three children as "it" so everyone gets a turn at being "it" even in a sizeable group