Lake Lansing Park South is out, along with most other city and county parks. They close just after sundown (about 1930 in early October), and alcohol and fire regulations are probably too onerous for the horde to abide.
The idea of a bonfire has been floated. I like it. It'll be the perfect time of year for it and I haven't done one in maybe 10 years. That puts us in a state park - which, conveniently, also offer campsites, and generally allow getting lit and getting things lit. There's a poll up as well, to get an idea of what people would prefer. I imagine some people would rather just go to a restaurant or bar for a couple of hours in town. Go ahead and vote and/or post some suggestions here, we'll see how it goes. It's only early July right now, we've got a while before we have to start locking down our choices.