The University of Nottingham has created a collection of short videos about sixty commonly used symbols (or concepts) in physics and astronomy. From Eigenvalues to Theremins, each video is about 5 to 10 minutes long, provides a "fun chat with men and women who love their subject and know a lot about it!" and often includes an interesting demonstration.
To start watching visit or http://www.sixtysymbols.com/ or view the short Transistor video below.
Also available from the University of Nottingham, the Periodic Table of Vidoes