They were dancing up in Harlem. Down in Union Square. Can’t forget Fort Greene. There was swingin’, swayin’, and boom boxes playin’. To be in New York on the night of November 4, 2008, just after 11 p.m., when the presidential election was called for Barack Obama, was to be reminded that our streets are made for expressions of spontaneous joy. Despite the forces that atomize our lives more all the time, the urge to take to the streets remains deep. Sometimes people are propelled by anger, as after a controversial shooting; sometimes the gravitational pull is shock and sorrow, as it was when thousands gathered to grieve and debate in parks after September 11. But the communal compulsion is an amazingly hopeful phenomenon, no matter what the circumstance, especially because in New York there are so many impediments, so many reasons why it shouldn’t keep happening, from the sheer scale of the city to the stark economic and cultural differences of the people who live here. Yet maybe those are also the greatest reasons why people rush into the streets in huge numbers to celebrate everything from sports championships to election victories: the need to connect, to come together, right now, as one, to share our happiest moments, and to do it against the most dramatic urban backdrop imaginable.