J.R.
I have been to birthday parties at McDonalds that have the play area, Circus Pizza or one of my favorites would be Edinbourough Park in Edina. The Edinbourgh Park has a relaxing area with indoor waterfalls and trees, it also has the climbing area (like McDonalds play area -but much nicer)and a moonwalk that costs $5.00/person though. Edinborough does have an open gym area (with balls, and scooters) that is free and they had a small playground that was free. One completely free park is Chutes and Ladders at the Highland Park Reserve in West Bloomington. That has a HUGE array of tunnels and slides for older kids and two smaller parks for the younger kids. It is also on the lake so it also apeals to adults and kids and gives you a nice place to begin and/or end the party.
Good luck