According to my Google Geek Holidays, December 5 is the official “Day of the Ninja“. Indeed there appears to be a grass roots effort at making this official. Now I’m all about holidays but not sure exactly how much traction this effort is going to get. Nevertheless, if you are in the mood to wear all black to work, today is the day. I would, however, recommend leaving the ninja sword at home. Razor sharp swords at the workplace are usually a bad idea.