Let me begin with the boring little detail that ruins everybody’s fun: there is no known ongoing police investigation. That means we are left with the usual American pastime, trying to separate actual facts from gossip, hysteria, and the kind of eyewitness drama normally reserved for UFO landings. The Blue Dog is a small but popular restaurant near Sepulveda and Ventura in Sherman Oaks. It serves very decent burgers, which I can say because I’ve eaten there several times and somehow managed to survive without becoming part of a national incident. Apparently, Britney Spears was there with her personal assistant and bodyguard. The story, as it has been served up, medium rare and heavily seasoned, is that Britney was telling a story, perhaps a little loudly, about a barking dog. At some point, she was also cutting her burger with a table knife. Yes, a table knife. At a restaurant. Near a burger.  Call the FBI!. Now, anyone familiar with the Blue Dog knows the tables are packed to...