In wake of tragedy at Boston Marathon, fans in New York and Boston have (temporarily) united

No two sports cities in America likely have a more contentious rivalry than New York and Boston. Fans of the Red Sox and Yankees, Patriots and Jets (or Giants), Celtics and Knicks and Bruins and Rangers usually boo one another (or worse) at games and take joy in their rival fans' disappointments. This week, however, the feeling is much different -- just as it was after 9/11 and Hurricane Sandy. My story for ESPN.com's Playbook section: http://espn.go.com/blog/playbook/fandom/post/_/id/21059/for-now-a-bond-between-boston-and-nyc