You need at least 12 children, or 10 children and two adults, to make this game worthwhile. It can be noisy but it's a good way to help a group of children learn each other's names, and "bond" a little with the other kids in their team.
You will need:
A large, solid blanket or curtain.
Divide the children into two teams and get each team to sit on the floor on opposite sides of the room. Two adults or children stretch the blanket between them to form a divider.
Now one team chooses one of their members to crawl up to the blanket and sit behind it, quietly. He should face the other team. The adults drop the blanket and the other team races to identify and shout out the child's name.
Once the children get to know each other a little, the chosen child can sit cross legged facing away from the other team, with his back to them. Alternatively he could sit facing them but be instructed to make a funny face to distract them!