I'd teach a course on 'Low-Brow' underground poster art. It combines my 3 main interests of Music, Art and Wierdness combined, and the creativity in this field is absolutely mind blowing.
I got into it after working at the SXSW festival in Austin back in 2004, where there was a poster convention called Flatstock, where loads of the top poster artists in America gathered to show off their work. At the time it blew my tiny mind, and inspired me to come back and start making posters for bands etc myself but as I've had to work at my career this has kind of taken a bit of a back seat over the last few years but sometihng I definitely need to get back into doing a bit of again.
Just realised I've mentioned Austin twice in 2 questions, your mystery Q's are reminding me of some really great memories :)