You can see clips from the show here!

Zombified versions of Les Miz and Mama Mia after the jump!

Richard O’Brien was an unemployed actor living in London when he came to write They Came From Denton High, later called The Rock Horroar Show, soon to be famous as The Rocky Horror Show (1973).
The Rocky Horror Show sort of came together rather than being worked out in detail; rehearsals started with a bare-bones script that was embellished by the director and cast, with the actors providing their own improvisations which then became canon. Some of the songs O’Brien had rattling around for years: “Science Fiction Double Feature” was written for a party at an Elstree film studios, “Super Heroes” and “I’m Going Home” were tunes O’Brien had doodled with for ages and “Touch-a Touch-a Touch Me” was a late addition when director Sharman noted “We need a song here.” “The Time Warp” evolved in rehearsals to give the three household retainers something to do. “Eddie’s Teddy” was added for the move to the show’s second venue, the Chelsea Classic. Though it does not appear on the cast album, it was released on 45 by O’Brien and his then-wife, Kimi Wong (she is the Asian Transylvanian with the long hair) as Kimi & Ritz.
Brian Thompson’s ingenious shoestring set consisted of little more than a couple of platforms, an old Coke machine and some tubes and wires for the lab. In a move of pure genius, he erected scaffolds and draped tarps around the space to suggest a cinema in the process of demolition (indeed, after the Royal Court engagement the show moved to an actual cinema, the Chelsea Classic in the King’s Road). The actors clambered over the scaffolds and played in front of a sagging, dusty movie screen, as if the flickering images of a thousand forgotten films had suddenly popped into three-dimensional life. Thompson’s settings put bones into the shapeless body of the work, just as his designs for the film version placed the story in a setting that, rather than mere background, provided context and coherence to the proceedings. But that is in the future. 
Richard O’Brien originally planned to play Eddie – sing one song and then retire to the green room, collect paycheck – but Sharman convinced him to play the sinister Riff Raff instead. Marianne Faithfull was sought for Magenta, but Patricia Quinn snagged the role. She accepted the part on the strength of the opening number, "Science Fiction Double Feature," which she sang as an ice cream-vending Usherette. Her agent warned against taking the role sight unseen - after all, what if there were only four lines? It turned out there were not many more than that - it depends on which iteration of the script, but there are fewer than 20 - but Quinn's turn as Magenta in the play and film is nonetheless indelible. (Surely I am not the only one who sees Riff Raff and Magenta as the descendants of Lolita's Claire Quilty and Vivian Darkbloom, lurking on the sidelines with mocking smiles, planning the protagonist's downfall?) Columbia was a late addition to the story – Little Nell used to clean Jim Sharman’s apartment, and he thought the spunky, tap-dancing Australian deserved a role, so Magenta’s part was split in two (à la Eddie's brain) to accommodate her.
Richard O’Brien met Tim Curry outside a gym while scouting for muscle-men to play Rocky. Sharman and O’Brien had considered an actor called Jonathan Kramer for the role of Frank, but Curry’s audition blew them away – he ripped through Little Richard’s manic “Tutti Fruitti” and the show had its leading man. Curry's Frank N. Furter was originally a bleach-blonde. His hair later was dyed blue before reverting to his natural brown ‘fro. Curry flirted with a Lugosi-like “Transylvanian” voice, then an American accent, before settling on the familiar posh “Kensington” intonation. The American-accented portrayal is enshrined on the original cast album. When Tim Curry was indisposed, O’Brien would take over the role of Frank – in fact, when film producer Lou Adler saw the show and decided to bring it to 20th Century Fox, it was O’Brien vamping it up instead of Curry. One longs for a recording or photo of O’Brien as Frank to surface!
The show premiered on an appropriately dark and stormy night in June 1973, with legendary horror-movie ham Vincent Price in the audience, as if giving his dark blessing. What must have that first audience thought, as masked ushers silently thrust mimeographed programs - with a crude illustration by Richard O'Brien himself - into their hands, then climbed onstage to whip the tarp off an Usherette, as if she were yet another mothballed relic of the cinema's past glories?
The sound is garage-band crude and the singing more enthusiastic than accomplished. And yet this record is, for me, the definitive Rocky Horror in many ways. It’s rawer, crazier, and just plain more fun than any version that came after. This is Rocky when it was an impromptu labor of love, staged in a dusty old theater on a shoestring budget. You can just hear the relish with which the actors jump into their roles. The band attacks these brand-new songs with a gusto that almost makes the polished movie versions seem tame. “Sweet Transvestite” is sleazier than ever, all piano and cowbell and squawky guitar, with Tim Curry oozing oily charm and Brad’s verse “rapped” in time to the music. "Touch-A Touch-A Touch Me" has an innocence that all other versions lack, and Chris Malcolm's performance of the oft-deleted "Once In A While" has never been bettered. Curry’s rendition of “Whatever Happened to Fay Wray?” on this disc is unequalled, especially his “Whoa-oh-oooh, don’t dream it…!” The pounding Jerry Lee Lewis-style piano on “Wild and Untamed Thing” never fails to get my heart rate up, and Frank’s breakdown in “I’m Going Home” is hilarious. “I - I’m sorry, I can’t go on,” he sobs. This is the Rocky Horror ur-text, and its cheesy charms seduce me every time.
Imagine seeing a live production and never hearing the audience anticipate every joke or throw back their own comments, but rather being allowed to experience what is on stage. Rocky Horror helped define a moment in pop culture that has resonated through the intervening 30 years - glam rock, goth, punk, gay liberation, Baby Boomer nostalgia, all have made their mark in Rocky's wake, and all have robbed the original of its status as a uniquely fabulous beast. The wild and untamed things that cavorted on stage at the Royal Court are now VH-1 relics and Hot Topic commodities. How transgressive is a sweet transvestite when the malls of America routinely host fishnet-hosed, black-lipsticked baby goths? Don't get me wrong, I am glad to live in a world where such things are commonplace - but I can't help mourn what is lost in the process.
The Rocky Horror Show Book by James Harding is a large format book focusing on the original show and the touring productions. Most of the pictures of the original London cast in this article appeared in Harding's book. It's also out of print, but not impossible to find.