"Back to the Future" Day has arrived. In "Back to the Future Part II," Marty McFly travels to October 21, 2015, to save his children, yet to be born in "Back to the Future's" 1985. What did 'Back to the Future II' get right? The predictions of "Back to the Future II" are hit or miss: big-screen flat TVs, yes, Mr. Fusion, no; virtual-reality goggles, yes, "Jaws 19," no. What more gurus ?