Ah, The Rocky Horror Picture Show.
Watching the movie is fun, but the live version is so much funnier, assuming you've been/are going with a group of people who understand the culture and have no qualms whatsoever about adding your own dialogue at the proper time.
This is, for example, the opening song. Typical additions added in italics. It's NSFW like most of the rest of this show. Spoiler for consideration.
Michael Rennie was ill the day the Earth stood still,
But he told us where we stand (on our feet!)
And Flash Gordon was there, in silver underwear (it was gold!)
Claude Rains was the invisible man (I saw him!)
Then something went wrong
For Faye Wray and (fucked) King Kong,
They got caught in a celluloid (sexual) jam.
Then at a deadly pace it came from outer space (it came on Janet's face)
And this is how the message ran...
I'll spare you the rest of the lyrics, but needless to say there's a new addition every few lines or so.
Of course, when performed live, there's always the opportunity for imagination. At one point, bad stuff has happened, and the narrator breaks out, "But what, exactly, was over?" As well as "What further indignities were they to be subjected to?"
Depending on who the narrator is, all *kinds* of amusing comments come from the theatregoers. My particularly memory of the above was with Michael Aspel as the narrator. What was over? Cue: "Your career!" from the crowd. Further indignities? "Antiques Roadshow!"
You have to understand, the humour in RHPS is basically English humour, even though the cast isn't what you'd call English.