Hamlet – A crossword puzzle game using regular expressions
regexcrossword.com
regexcrossword.com
However, I find this site a bit frustrating. I love the idea, I love that they have so many puzzles, and I love the UI they've built. But I don't want themed puzzles that I can solve without having to crunch the regex themselves – if I was interested in that, I'd do a regular crossword.
It looks like a squatter has gotten ahold of coinheist.com; a correct permanent link is
http://www.mit.edu/~puzzle/2013/coinheist.com/rubik/a_regula...
The solution (with author credits) is at
http://www.mit.edu/~puzzle/2013/coinheist.com/rubik/a_regula...