Freedom Park is awesome. I like biking through the park on the greenway along the creek. There is also the path around the huge pond, but that can get pretty crowded. I once tried to rollerblade (yes, I know, soooo 90s) around the pond and it was pretty much an obstacle course of joggers, babies in strollers and dogs. It's also a great place for a picnic.
I saw a movie in the park there this past summer. It's a nice idea except that the event is sponsored by a church and they spend a lot of time trying to get you to join.
Also, be warned: There have been car breakins there. Don't arrive at the park and then put your purse in the trunk. Thieves are watching out for that kind of thing and seize on the opportunity.