I'm currently enrolled in Software Carpentry's Online Instructor Training and our most recent assignment was to make a 2-3 minute screencast to motivate the usage of a tool or idea one might cover in a Software Carpentry Bootcamp. I choose to do mine on GitHub.
There are some things I don't like about it (should have zoomed in on the browser as the editor & terminal become distracting, could have used some bullet points in the outro) but overall I'm happy with it.
If you're at all interested in leading a Software Carpentry Bootcamp, I highly recommend the Instructor Training. I've learned very interesting ways to approach teaching & evaluating what I've (hopefully) taught.