Can Boston win the grand slam of championships this year, winning the title of all four major sports in the same year? OK, probably not. But as the basketball and hockey playoffs about to start, it is a uniquely exciting possibility for the city of champions. At a minimum, both the Celtics and the Bruins have a good chance of reaching the conference finals, and even that would be amazing considering the Red Sox and patriots have already won their respective leagues. Anyway, should be fun to watch.