"Jump Off 15th," courtesy of Seattlest Flickr user JeanineAnderson Seattlest, as you know, has long been an advocate of playing hooky on Friday. Today, if you're looking for an excuse to cut out early, just tell your boss you can't bear to sit in the office any longer on the Happiest Day of the Year. How did "they" figure out that today is the happiest? A simple math formula, of course: "According to the......