Peshastin Pinnacles is a day use state park located just outside of Cashmere off of Highway 2. Picnicking is allowed there, but the primary attraction are the trails that lead up to the top of the interesting rock formations that are found there. Here is a nice looking video taken by some hikers on a gorgeous Wenatchee Valley day.
[youtube]http://www.youtube.com/watch?v=rh7CZPK8U80[/youtube]