Use one less sheet of paper than the total number of children. When the music starts, the children walk in a circle. When the music stops, everyone scrambles to land on a sheet of paper. Whoever winds up without a sheet of paper plays the music for the next round. The first group to come back with all the items on the list wins.
Kids love magicians and clowns.
If you're hiring outside entertainment, make sure you see the act beforehand or get a reference from a trusted friend. When it comes to easy entertainment, animals are a no-brainer. Pony rides and petting zoos can add excitement to your party. Everyone will appreciate your having the party at a time that allows for a nap before or after.