Ted Talks is really cool. From technology to politics, theories and writing, a bunch of different speakers talk for under 20 minutes about anything under the sun. Constantly updating, I've just barely tapped into it, but is always a good choice. http://www.ted.com/talks
Radio lab is neat. No video, you just listen to some guys talking about different events in history. I heard a story about a guy who got bombed in Hiroshima and Nagasaki. Powerful stuff. http://www.radiolab.org/
You can also see QI on youtube. Its a joke gameshow where comedians try to answer really interesting things that very few people know. They are all bewildered by the answers. How many moons does the earth have? Well, one is not the right answer.