Dress them (and you) in play clothes, go outside, and get dirty! Kids naturally love to play in the dirt, dig holes, and play with insects.
When I was very young, my sisters and I played in the dirt a lot. There was a shady place in our front yard near a small pine tree where grass wouldn’t grow. In the Summer, we would go outside to that pine tree and play, nearly every day. We would make roads for our cars and tractors to drive on, little pastures for our plastic farm animals to graze in, and tiny gardens beside our Playskool houses. The gardens were lined with stones we stole from the driveway. We drew rows in the gardens using a stick as a pencil. The insects that happened to stop by were critters.
I remember my dad would say “I guess I will have a nice yard when the kids are all grown,” and he did. He always said he would trade his nice yard in to have those times back.
We would come in the house filthy dirty (as my mom put it). Mom would put us straight in to the bathtub, where our adventures continued. Of course, we had soap eating washcloths that liked to lick the dirt off our skin. Plus, a few plastic bathtub toys.
So, let your kids get dirty. Playing in the dirt is just plain fun!
Tip: Watch your kids when they are little, and be sure they don’t eat the dirt. Always be sure they wash their hands and even take a bath or shower after playing in the dirt. Be sure to wash any toys they use outside. There can be harmful microbes or bacteria in soil.