If you can take music out there, kids that age LOVE "freeze dancing." Play some fun, groovy music and every so often pause it. They dance when the music is playing, but freeze in place when the music stops. Another fun game I call Pirate's Booty. I made cards on 3X5 cards with some sort of instructions on them. Kids take turns to get up from the circle and draw a card. They have to do what the card says. You can either have them do individual things, like "j`ump up high and wiggle" or have the whole group do it together. I follow the pirate theme by having a "Captain's coming" card (for a stand up straight and salute) a "hit the deck!" (for lay on your tummy quickly) Another fun thing to do is fill a few rubbermaid flat boxes or dish tubs with sand, dirt, or something similar and bury the pieces to a puzzle in it. Have the kids work together to dig the pieces out and then put it together. If you have two or more, they can race. Also, one piece of advice I have learned the hard way: If you play games like duck, duck, goose or especially musical chairs, always have a gift, like a lollipop, to give the kid as he or she gets "out" so they don't cry and feel left out.
