Here's CommonCraft's channel on Blip.tv.
There are any number of ways of explaining complex systems. Duarte Design is another company based out in Silicon Valley who has built a business on information design. They produced Al Gore's presentation 'An Inconvenient Truth' and if you've seen that, you know that it's probably the most interesting two-hour Powerpoint presentation you've ever seen. (Although they did it in Apple's Keynote.)
CommonCraft wows you with clarity rather than production values. They're not the first to use this paper cut-out technique or draw diagrams on a whiteboard, but they're great at distilling out the information that's relevant and putting that into a two or three minute spot that doesn't bore you to tears while you're watching it.