I spent the weekend substitute teaching for Michael McCarthy's writing classes at the iO. Here, I'm showing the Sketch-writing class Monty Python's Joke Warfare/Funniest Joke in the World Sketch as we study editing (an appropriate choice on the Python anniversary weekend, I thought). 
This was my first time teaching in the new building, and I'm still amazed just walking into the place. I always have to think back to the crumbling, barely building-code legal Crosscurrents cabaret, where the iO (then ImprovOlympic) first started; to say it's come a long way is hugely underestimating it.
I highly recommend anyone in the Chicago area stop by for first-class improvisation (or, in the case of Dave and TJ's Mission Theatre, first-class sketch comedy), and stick around for drinks and dinner as well. It's only been a couple of months in the new building, but it's fast becoming a landmark. In fact, it's the Great Wall of China of Improvisation. Go now and thank me later.