I ran across an awesome picture of Einstein blackboarding E=MC2 recently.
Check it out over at From Quarks to Quasars here.
From the description:
Einstein offered a series of public lectures throughout his career. At one lecture, which was given in Pittsburgh in 1934, Einstein mathematically derived his mass-energy equivalence equation (aka E=mc^2). What you see above is an image taken at this lecture.
It is believed to be the only remaining photo that shows Einstein working on this derivation.
It really is too cool.