I was here. What were YOU doing, handing out candy to the kids who came to the door? Did you miss this ride too? Don't miss the next NYC Critical Mass. GET IN THE PICTURE! There is no charge, because there's no one to pay. It is simply a NYC phenomenon....When enough bikes accumulate, they begin to mill around, and after awhile, one or two take off and all the rest sort of ...follow! They form up at 7:00 PM at the North end of Union Square Park (17th St. & Park Avenue)on the last Friday of every month. All that you need is a bicycle or a pair of skates.