At the 6th meeting for the BitcoinNYC Meetup group, an idea was proposed to have an open-air Bitcoin marketplace. It was agreed upon that this was to be held on the southern steps of Union Square in New York City on Monday, May 6th, 2013 from 4 to 8pm. Modelling itself after the early days of commodity trading, this event hopes to bring Bitcoin buyers and sellers together in one specific area so that they can make deals in true free market fashion.
Details and RSVP to the event (not required but useful for getting some group excitement going) can be found in the event link on the BitcoinNYC meetup page.
UPDATE: This event has been officially cancelled by the BitcoinNYC Meetup group with the following note: “At the behest of legal council I am officially canceling the meetup for this event as to promote commercial activity at the park would require a permit, that said if you guys want to just hang out at the park that would be fine.” [emphasis ours]