We've been there a few times, and it's been fun. They have a decent miniature golf course, batting cages, a go-cart track, and a playground. They have shelters where you can have a group picnic, and they have an indoor room where you can host a party. They've added inflatables and a climbing wall as well. The staff there is really friendly, but they haven't done a lot of upkeep on the grounds, as a lot of the fencing or walls and things don't look like they've seen much for maintenance since they were first put up.
Home of the Des Moines Renaissance Faire, in a permanent setting (buildings, a "castle", real restrooms, shops, food, etc.) First three weekends in Sept.
Not worth the money. Unless you like waiting for hours for a minute ride on junk that don't work. And the staff is RUDE!!!