How you support the Koch brothers
Growth of U.S. Government Spending Over Time
Not exactly a video, but an interesting interactive graphic - here's a link to the page that shows it full-size
112 Years of Election Maps
The U.S. of Electoral Map
A History of Political Ads
How the Electoral College Works
It's not a video, but click here for a NPR story that asks "Do voter ID laws prevent frauds, or dampen turnout?