Microsoft Research, in collaboration with Microsoft Corp. Chairman Bill Gates,  makes the Messenger lecture series by physicist Richard Feynman freely available to the general public for the first time.  The Messenger Series explains the relation of Mathematics and Physics.

If you have ever read any of his books, you will really enjoy seeing and hearing the man in action.

To view the lecture series, you must first download and install the Silverlight plugin, similar to installing a Flash plugin.  However, installation is simple and works seamlessly on a Mac.  View the Lecture Series