Last week, I gave a quick informative session to my fellow ITP students (a "Drive By" in our parlance) called "Don't Lose Your Shit: Version Control and Backups". I covered why you should care about version control, outlined the basic concepts, explained the difference between centralized and decentralized systems, did some some demos of using Git, and showed why GitHub is awesome. Then I did a quick five minutes on backups.
It was interesting to try to explain version control from scratch to a relatively less technical audience. I've taught git before to teams of developers who were already used to using Subversion in their daily work. This group ranged from people who had never even heard of version control to people who were comfortable with SVN and were mostly curious to learn about Git and GitHub, specifically.
I tried to be relatively straightforward about the differences between centralized and decentralized models, but I'm afraid my bias may have come through a little bit.
Anyway, in case it's useful to anyone else, I'm embedding the slides below. And, of course, the keynote and my notes are available on GitHub.