Chess CAPTCHA
Brilliant building of software. Less than brilliant copy.I would change  Black plays; checkmate in one!
  This is a chess CAPTCHA.
  Click on the board to make your move,
  and prove you are human.

to  This is a chess CAPTCHA...
  To prove that you are human,
  click on a black piece, then
  click on the only destination
  square that will checkmate.

I really don't mean to nitpick, but took me a minute to figure out what to do. Sometimes the thing that makes the biggest difference for us programmers is not our communication with our compiler but our communication with our users.Great job. Thanks to you, I just announced I won't be ready for brunch for another half hour.  Sigh.