This is probably the standout ledge over stairs spot New York has to offer. Facing 42nd Street is a foot-and-a-half high, four-and-a-half foot long marble ledge over five stairs, with a five foot drop at the end. The ground for the landing and runway is absolutely perfect, although the surface of the actual ledge may benefit from some wax. There's also a ledge with the same height over a three stair, although it only has a fraction of the drop. Next to it are two thirty foot long, two foot wide, foot-and-a-half high marble ledges running in a sequence together. All of the ends are waxed and they could be used as manual pads as well.
Usually, you get a fair amount of time here before getting kicked out by some guard with a dog. There is a guy sitting in a desk directly in front of everything there is to skate but he doesn't care if you skate. If anything, this is an early morning or late night spot because it is in one of the most tourist populated parts of the city, which would force you to have lookouts to ensure you're not crashing into people when you skate the five stair ledge.
Sixth Avenue in between 42nd Street and 43rd Street. Take the B, D, F, V or 7 to 42nd Street-Bryant Park and the spot is half a block away, if not right outside depending on which exit you come out of.