If you were a New York architect in 1931, the height of your social season was the Beaux-Arts costume ball. That's when fancy dress consisted of a costume based on your most famous architectural design.
Here are the architects and buildings in question, courtesy of Archive Digger:
New York's Architects dressed up at the 1931 Beaux-Arts costume ball as the buildings they designed. From left to right: A Stewart Walker as the Fuller Building, Leonard Schultze as the Waldorf-Astoria, Ely Jacques Kahn as the Squibb Building, William Van Alen as the Chrysler, Ralph Walker as 1 Wall Street, D.E. Ward as the Metropolitan Tower and Joseph H. Freelander as the museum of New York.
I'd love to see something like this today—not just for people whose buildings have come to fruition (although someone will have to be the Burj Dubai), but for architects as well. Richard Aurele in particular needs to get in on this act as Bob, the Dog Building of Shanghai.
You can see more photos from this party on Retronaut.