Update — Winter 2016: Spot has been torn down.
Most of the ledges here have been blocked off by planters, and the steps have bumps bolted into the ground right before them. There are still two ledges that run over a handicap ramp and a bench to square rail out front. The flat on the lower level is quite good as well.
Bust — ♦♦♦♦♦: There are “No Skateboarding” signs posted all over the plaza. Security will usually come out in a matter of minutes to tell you to leave. Better at night.
Location: 54th Street and 6th Avenue. Take the F train to 57th Street and skate south for three blocks on Sixth Avenue.
Pictures (Click to Enlarge):