Book in advance, fills fast.
You drop your kids off. They give you a pager and you sign away their liability. The kids put on lifejackets and bandanas and get on a boat with a few CMs and go treasure hunting. They stop by the marinas of all the Bay Lake resorts, find treasure, and two hours later you pick them up - they have a bag of rings, spiders, necklaces, a little candy and probably still have their lunch (uncrustable, juice box, gummy bears, rice krispy treat).
They have a great time. Its geared for the 5-6 year set, 4 year olds can go (and there are plenty of them) and older kids can go (up to 10, I think) but I would think anyone older than about seven would be too old.