Unfortunately this is an event with the kind of essence that cannot be properly explained. It has to be experienced, but nonetheless I'll try.
First go see the film, or better yet, trust me that you will have the most hilarious, fun-loving, uninhibited time and just go completely ignorant of what to expect (through preferably dressed in drag).
Your other option is to do a little research and learn that the Rocky Horror Picture show is a 1975 British comedy/musical that satires science fiction, B-horror movies, and contemporary notions of sex, gender, and politics. Soon after its release it became a midnight movie, cult classic, and now it is performed all over the world in unique fashion; while the film plays on screen, actors perform in front of it. But that's not all, The Rocky Horror Picture show is all about audience participation and whether you're calling Janet (Susan Sarandon) a "slut!" or dancing The Time Warp, you are certainly never bored.
Beyond being an evening of frivolity, The Rocky Horror Picture Show in Montreal is special because it is housed in the Rialto Theatre (1923), a National Historic Site of Canada. Furthermore, at the Montreal show one instantly feels welcome amongst a group of total strangers. No matter what your fetish is, or if you're young or old, as long as you come with an open mind you have a good chance of leaving with a group of new friends.
