Emcee

If there is no preshow the emcee might be an usher or theater management who just welcomes the audience, explains any theater rules regarding prop bags, thanks any movie sponsors, then asks the audience to enjoy the movie.


If there is a preshow some of the duties of emcee are...

"The Emcee of the show should explain the theater's rules loudly and clearly during the pre-show... The pre-show should be coordinated by the President, but should be run the Emcee, which should be the same person every week. In your pre-show you should always mention the names of the performers for that night, as well as information about how to reach your cast online, the RHPS Official Fan Club, and info about how to become a part of your cast.

http://www.rockyhorror.com/participation/transuniv.php


Denton High Drama Club list emcee duties as follows...

Pre-preshow Announcements (raffle tickets, prop bags, Facebook page, how to join cast and crew, etc)
Welcome
Reading Of The Rules
Conduct Costume Contest
Call for Virgins, Crowds may chant back, “WHATCA GOING TO DO TO THE VIRGINS?” to which the MC will reply, “We’re going to pop some cherries tonight!”
Virgin Pledge
Host Virgin Games
Introduce Any Live Acts
Post-Preshow Announcements (raffle tickets, prop bags, Facebook page, how to join cast and crew, etc)
Drawing (raffle tickets)
Cue Projectionist (have audience spell R-O-C-K-Y ("give me an R", etc) or chant "lips, lips, lips")
Introduce Shadowcast (at end of movie with movie cast credit pictures)
Closer (meet in lobby for photos, thank you for coming, we are the (blank) shadowcast)


One famous Rocky Horror Picture Show emcee was Sal Piro, "Sal Piro is the president of The Rocky Horror Picture Show Fan Club, a position he has held since 1977. Piro was a part of the original Waverly Theatre audience, from which the unique audience participation elements and much of the film's cult following were born. This following has gone on to become a worldwide phenomenon." - Wikipedia