To the west of the main building, the Hour Motion Picture Theatre opened in 1910. The space to the east was converted into a Venetian garden in 1913 and was used for movie screenings. According to the New Yorker, it became one of the first film production lots in the world after one of John Kolle's sons, Herman Kolle, founded the Crescent Film Company with Fred J. Balshofer and began making movies for nickelodeons. Old advertisements for Prospect Hall described the "high-class motion pictures and vaudeville" that were displayed every night, as well as "country butcher shops" on Tuesdays and "safe and sane" Independence Day events every July 4. Over the years, the frequency of high-profile events at Prospect Hall, including political meetings, decreased. It continued to be used for events such as an October 1929 debate between mayor Jimmy Walker and ex-governor Al Smith, as well as Works Progress Administration productions during the 1930s. The main ballroom was used for vaudeville and movie screenings during the summer between 1936 and 1940.
