Two things I forgot to mention about the rocking city-wide melaveh malkah last night:
Outside BJ, on the sidewalk across the street, was a klezmer band, with an entourage wearing 1920s-style (I think) clothing, holding a sign saying "We are the Sukkos Mob". Some of the overflow people from BJ were dancing to the music. Does anyone know who they are? There's only one Google hit for "Sukkos Mob" -- they're listed as part of the DUMBO Art Under the Bridge Festival, which apparently was this weekend, except that the Upper West Side is not so close to DUMBO.
Inside BJ, S"Y and others were beatboxing into the mike during the dancing, and then freestyling later on (after the official proceedings had ended), so we were treated to the hiphop remix of "Ki miTziyon".