Insipred by the 15 minute weblog, I created a demo of Ruby on Rails for my colleagues.
The material for this demo is listed below. The presentation is used to explain concepts, and to illustrate elements of the case we use. The speaker notes contain instructions on the order in which to do stuff on the command line, in the text editor, in the browser, and when to point out something using keynote.
When typing like a maniac, you should be able to get through this in about an hour. Have fun!