a huge area of prairie grasses
and woodland forests.
My kids love the playground.
There is also a nature center, a butterfly garden, and even a stargazing observatory.
I have posted a few times about their different activities for children and adults, and they feature prominently on my free fun activities calendar on the right. Here is the post I made about their online (free!) educational resources. Here is a post that I did on how to extend the fun anywhere you go.
Focus one time on plant life, once on animal life, have a scavenger hunt, or just go out and enjoy the beauty of nature.
Here's an interesting map of all the parks in Story County. I think we've visitied most of them, but I found a couple we've missed. It looks like this map might work for looking up county parks wherever you live in Iowa.