Ruby Skye is a popular nightclub in the Tenderloin neighborhood of San Francisco, California. The nightclub is housed in the Native Sons of the Golden West building at 420 Mason Street, built in 1890 by architect August Headman. The nightclub is housed in what was originally an auditorium/meeting hall. In the 1940s it became a USO club and was called the "Stage Door." Later it started showing films as the "Stage Door Theater" and hosted the premiere of the Alfred Hitchcock film Vertigo on May 9, 1958. By the early 1980s, it had become the Regency III movie theater (the Regency I and II were located several blocks away).