Have the kids play those age-old outdoor games you remember playing as a kid. Play circle games, such as "Duck, Duck, Goose," or "Who stole the cookie from the cookie jar?". Being at a park means there is plenty of room to run around without fear of the kids running into anything. For 2- or 3-year-olds, lead them in simple games like "Ring Around the Rosie," or "London Bridge." With a battery-operated CD player, you can have all the kids play freeze dance.

Other classic games for preschoolers include, "Red Light, Green Light," where the kids run on green and must freeze on red; and "Red Rover," where they have to run from one side of a designated area to another without getting captured. Keep it non-competitive to avoid tears and tantrums by keeping everyone in the group even when they get caught.

Bring an old sheet from home to play parachute with the kids. You will need a few other parents to help you hold the corners. Have the children fill in between the adults, holding onto a piece of the sheet. Lift up the sheet and let the kids run inside to sit under it as the "parachute" comes back down to earth.

When they get bored with the parachute, break out the bubbles. Bring non-toxic bubble solution, large baking pans to pour it in, and kid-friendly over-sized bubble wands with soft handles. You can also have the kids toss oversized, lightweight bouncy balls to one another. If there is a sandbox at the park, hide a few soft, rubber toys in the sand. Give toddlers little plastic shovels to find the buried "treasure."

Arts and crafts are an ideal way to keep the kids out of your hair while you are setting up the food or birthday cake. Spread a huge sheet of craft paper on a picnic table. The kids can gather around and draw pictures anywhere on the sheet using non-toxic crayons. You could also write out the birthday child's name in bubble letters and have the kids color them in. Have the kids collect items such as leaves and twigs from around the park for nature collages. Recruit the other parents to help you monitor the kids closely to make sure no hard, small items are picked up, such as acorns. Give kids brown or white paper goodie bags to color and decorate.

Bounce houses are popular for outdoor children's birthday parties, but when used improperly, can lead to serious child injuries, according to a study on inflatable bouncer injuries published in the Journal of the American Academy of Pediatrics in 2012. Although there are no national guidelines, the Child Injury Prevention Alliance encourages parents to keep their children under 6 years old away from bounce houses. Save yourself and the other parents some anxiety by skipping out on one for a toddler or preschooler birthday party. Plenty of other activities will keep the kids entertained. Small, inflatable slides that have just two or three steps and a short slide can present an alternative.