I'm for it! I'm in St Louis, but wouldn't mind the trip, would have to be on a saturday though.
Last weekend some friends and I went to Elephant Rock State Park here in Missouri and had a blast. There are huge rocks you can climb and forest to traverse... Any good parks in Illinois?
I'm up for anything though, even if it's someone's back yard. It would be great to get in touch with primal people that are even semi-local.