Experiments in large classes

I primarily use Aplia to do experiments, rather than problem sets. When I started teaching the 500-seater, one thing I knew was that I didn't want to give up activities like having students participate in a market auction but I couldn't imagine how that would work in class so I adopted Aplia.Well, as I mentioned a while ago, there were a couple of presentations at the TIP conference in January that downright inspired me and one was by Jose Vazquez-Cognet, at the University of Illinois, Urbana-Champaign, who discussed the double-oral auction that he does with his class of 800. To be clear, he does this in class, not using Aplia or some other computer simulator - he actually has 800 students milling around, trying to buy and sell from each other! I would never have imagined trying this in such a large class but listening to him explain what he does, it actually does sound do-able. One thing that helps is he creates smaller trading pits within the room: students can trade with those in their immediate area but they can't go running around to the other side of the room. He also has figured out a way to have students switch roles, from buyer to seller or vice versa, without having to pass out new information sheets. I'm sticking with Aplia this semester but am definitely tempted to give it a try next semester...