The film and its endearingly kooky and devoted subculture have been referenced in everything from Sesame Street to Fame to That ‘70s Show to Glee, which did a “watered-down, Disney-fied version” during its second season. (Instead of being from Transsexual, Transylvania, Frank-N-Furter, played by the Glee character Mercedes, is from Sensational, Transylvania.) Earlier this year, Fox announced a Rocky Horror two-hour TV special directed and choreographed by Kenny Ortega (High School Musical, This Is It) and executive produced by Lou Adler, who also produced the original.

It wasn’t always so. According to the National Fan Club’s president Sal Piro, who wrote a definitive history of the film, Rocky Horror’s countercultural traditions began when a group of regulars made a weekly pilgrimage to New York’s Waverly Theater. Sitting in the first row of the balcony, they’d scream for their favorite characters, boo villains, and adlib jokes that would be repeated at future screenings and codified into a kind of audience script.

From the roots of a rowdy small group of filmgoers, entranced by the film’s portrayal of transvestism, orgies, and unabashed sexuality as well as its campy charm, came a new trend: A shadow cast began performing the story beneath the screen. Their presence made every Rocky Horror screening more of a mini-musical-dance-party that was entertaining in its own right—if newcomers (referred to as “virgins”) weren’t familiar with the audience lines or the “Time Warp,” Rocky Horror’s famous dance-along hit, they were able to pick it up soon enough, and the sense of every screening being an event encouraged more newcomers to experience the movie.

Midnight screenings and new accompanying casts sprung up around the country as word of the New York-based spectacle spread among devotees. Young people who felt disconnected from society could identify with the film’s literal aliens, and for those from more strait-laced backgrounds, the initially conservative Brad and Janet’s presence gave them a way into a fantasy world outside their immediate experience. Still, the appeal wasn’t only in the film’s content, but the sense of community and way of thinking that came along with its almost-ritualistic conventions. As Roger Ebert wrote, “The Rocky Horror Picture Show is not so much a movie as more of a long-running social phenomenon” because “the fans put on a better show than anything on the screen.”

This combination of inclusivity and immersive entertainment became a key factor in Rocky Horror’s growing popularity. And as the nation became more welcoming of alternative lifestyles and orientations, the film became a not-so-cult hit, with “Time Warp” played at school dances and Rocky Horror allusions infiltrating popular culture, turning the film and its ostentatious fans into a reference point.