Check out Richard Feynman talking about various subjects!

Had it not been for Einstein, Richard Feynman, in my mind, is likely the genius of the 20th century. Check out a series of videos of him casually discussing different phenomena, all from a conceptual, physical point of view. It is really interesting how he thought about things. Of course, he was then a magician with math, and could take his physical pictures and models and represent them with the math!