A thank you to AM for the point.
This video is also a demonstration of the power of personal TV in the service of learning. Imagine how effective it might be with clickable print of unchanging textbooks. Instead of having to sit at a computer to watch, you could be waiting on a line.
Click and watch. Learn enough to let you know if you want to learn more. If you do, go on from there. If you don't, it's enough information for now.