I recently bought and put together the Batman Batmobile lego set. It was regularly $70, but it was on clearance and an "open item" at Wal-Mart for $20. I picked it up, intending on returning it if some of the parts were missing, but when I opened it up at home, all of the blocks were still in the bags, and nothing was missing. Took about 7 hours to put together.
http://assets.lego.com/upload/conten...BC255A79E7.jpg
Has all these moving gears and shit on the inside. The steering wheel makes the hood pop open, to reveal turbines that spin when the wheels roll. You can see the turbine's gears and shafts and stuff in the car. The rear wheels are a cluster-fuck of gears as well, that make the back turbines turn (and make fire twirl around like a jet engine). This thing is fucking awesome! I'm 23.