Egg Games
Play a couple of messy games using raw eggs with tweens. Of course, if you want to avoid a mess, you can use hard-boiled eggs. Tell the kids to select a partner and stand back-to-back with their partners. Place an egg in between the lower part of the kids' backs. Tell them they have to place the egg on the ground without dropping it. The first team to do this successfully wins the game. For another egg game, tell the kids they have to form teams of two, and give each team an egg. The players must toss the eggs back and forth to one another without dropping it. A team is out of the game if they drop an egg or if the egg breaks. The team that can toss the egg back and forth the longest wins the game.
Animal Games
As the kids arrive at the party, tape a slip of paper to each kid's back with the name of an animal on it, such as dog, cat, cow, snake, lion and chicken. The children must ask each other yes-or-no questions until they figure out what animal they are. The child who guesses her animal name first wins the game. Keep playing until they all guess their animals. For another animal game, assign animals at random to each child and then have the children play games of animal charades.
Soap Games
For large groups, divide the children into groups of five or six and give each group a bar of soap. For small groups, give each player a bar a soap. The players must work together to make their bar of soap smaller without breaking it or cutting it up. The players can rub the soap on the ground or use a bucket of water to try to make their bar of soap smaller. After 10 minutes, the team or player with the smallest bar of soap wins the game. For another soap game, you can place buckets or pails on the ground. Mark a line 10 feet from the pails and have the players try to toss bars of soap into the buckets. Award prizes to players who successfully toss the soap into the buckets.
Hunt Games
Make a treasure hunt for the kids by hiding several plastic gold coins around the play area. Give each child a plastic bag to collect the coins. The player who finds the most gold coins wins the game. For a variation, draw stars on a few of the gold coins, and the players who find these coins win a prize as well.