C.G.P. Grey is really kinda awesome. He has a series of videos called Grey Explains. Each video is short, but crams a ton of information (and more than a little humor) into its 3-6 minutes. Here are some of my favorites:
The United Kingdom Explained
The Difference Between Holland and the Netherlands (and a whole lot more)
Coffee: The Greatest Addiction Ever
Death to Pennies
Just awesome. I really need to watch each of these several times.