MashBlur

Google Doodles have often catered to the mathematically and scientifically savvy, but now there's one for word nerds.
Friday's doodle salutes the 100th anniversary of the crossword puzzle, an anniversary that will occur on Saturday. The first such puzzle appeared in the New York World on that date in 1913.

The doodle is an interactive puzzle; you can click on it to start filling in the clues.
For veteran puzzlers, the version on Google's homepage isn't too hard — perhaps on par with a Tuesday puzzle in the New York Times. The Times' crossword puzzles get harder throughout the week.
Of course, the puzzle includes a clue for Google fans, too: "Google's realm, with 'the'" (70-Down, three letters). After you solve the puzzle, you can share it on Twitter, Facebook and Google Plus.