Facebook has been on a roll with strange easter eggs lately, like turning your photos into ASCII art. But now a feature has been unearthed that was hiding in plain site. While you probably get bombarded with weird game requests from your cousin all the time, Facebook also secretly installed a game in chat that's a little less Farmville-y. By typing a simple message, you can challenge your friends to a game of chess.
If you type "@fbchess play" in any message, you can activate a game of it with a friend, like my hapless "I hate Facebook but need it for work" friend, Karl.
From there, a game board pops up:
Karl signed off before I could get a proper game going, which is all for the better, because I haven't played a game of Chess since Bill Clinton's first term. But in order to play the game, you essentially act like you would if playing the game by mail: specify the piece and set the move.
As you can see, the game is laid out as a grid such that a number and a letter correspond to a specific place on the chess board. To quote James Vincent at The Verge (see also: I seriously haven't played chess since 1995), "So 'Nbd2' will move the knight in the b file (the vertical column) into square d2."
Trying to type "@fbbattleship" did not, however, work. But Facebook, if you can see this, there's another idea for you.