A Physics Puzzle:
Today is the 100th anniversary of Einstein's publication of the paper containing "E=mc^2." (Actually, Einstein wrote "mass diminishes by L/c^2", where L is used instead of E to represent energy, and if you multiply both sides by c^2 you get the formula we're familiar with.)
In honor of the 100th anniversary, I wrote a crossword for today's New York Times celebrating the equation.
If you can't get hold of a copy of the Times, email me at [mylastname]@gmail.com and I'll send you a pdf.