If you can bear dealing with Internet Explorer and downloading the Silverlight plugin, there are a series of excellent lectures on science (specifically physics) by Richard Feynman. You know that old question of “who would you want to meet from history?” that people often ask? This guy is in my top three list.
He worked at Los Alamos on the bomb, he was a pioneer in Quantum Physics, and an all-around fascinating person. I highly recommend checking out all these lectures.
The first lecture in the series is on the Law of Gravitation, and its course throughout history.
Check ‘em out!