Northwestern's CATS group is an amazing mix of technical and creative talent, and I recently had a great opportunity to help people interested in web development get their feet wet. I decided to choose Sinatra, which I'm actively using at my work and which allows a greatly simplified introduction
to real web development.
Here's a link to the video: http://www.youtube.com/watch?feature=player_embedded&v=oDwZPXfCOYs
Also, here's a link to the associated Github repo: https://github.com/gnarmis/meerkat
Based on this experience, I'm hoping to teach a few more mini-courses in the coming quarters. Maybe RESTful services? Mobile dev? There's quite a few useful topics to choose from.