The Rocky Horror Picture Show is a cult classic musical-movie that spoofs old sci-fi and horror flicks, wich a ridiculous plotline and hilariously campy cast of characters.  It's unbridled fun to watch, and even more fun to experience at a public screening.  As the movie was not a great success when it released in 1975, it gathered a cult following, and many fans began to dress as their favourite characters from the film, shout callbacks at the screen, and bring their own props to interact with one another during the movie!  The RHPS still has a huge following, with midnight screenings all over the world annually.