Here are some good birthday party games to keep the kids entertained.

1. Pin the tail on the donkey - Hang a picture of a donkey (or horse, elephant, or any animal with a tail) on the wal. Blindfold the children one at a time and give each one a paper "tail" with tape attached to pin on to the animal. Whoever is the closest wins.
2. Giggleburst - Have each child lie down with head on another child's stomach. The first child says loudly "hah!", second says "ha ha!", and the third says "ha ha ha!" and so on till they all burst out laughing.
3. Obstacle course - Can be Indoor or Outdoor. Use chairs, bikes, toys, etc as obstacles and set up tasks the kids have to do as they go through, such as tossing a bean bag into a bowl.
4. Hot Potato - Have the kids sit in a circle. Give the first child a bean bag or ball and play some music. Whoever is holding the potato when the music stops is out of the game. The last one in the circle wins.
   A variation is to do this outdoors and use a water balloon.
5. Barnyard bingo - Collect pictures of animals from magazines and paste them onto Bingo cards. The bingo cards can be drawn by hand by the kids, or printed before hand on the computer. The parent calls out different animal sound, the kids who have the animal cover it up till they get bingo. You can use candy as the bingo pieces and let the kids eat them at the end.
6. Musical Chairs - Put out chairs in a row with every other chair facing the opposite direction of the chair next to it. Make sure there is one less chair than there are players. Play some music and let the kids walk around the row of chairs in a circle. When the music stops each child has to find a chair to sit in. Whoever is left standing is out of the game. Last one sitting wins the game. Make sure to remove one chair after each round so there will always be one less chair than players.
7. Treasure Hunt - Hids presents and/or candy treats around the room before the kids arrive (make sure to write down where you've hidden everything - even parents can have a tough time with this game!). Give each kid a paper bag to collect "treasures" in, and give them 5-20 minutes to search depending on how big the room is. It usually takes a bit longer when this is played outdoors. When the time is up, count each kid's treasures and whoever has the most, wins.
   A variation for older kids is to write up clues for them to solve to figure out where things are hidden.
   Another variation is to hide game pieces or tokens, and let the kids redeem them for prizes or candy at the end depending on how many tokens they have. Each prize can be worth a different amount of token.