**UPDATED 10/27/11 to reflect that the play's run has been extended.**

If the vaunted Internets are to be believed, at one point in the early 1990's Charles Ludlam's "The Mystery of Irma Vep" was the most-produced play in the United States. I find that astonishing. Not that the play is bad - it frankly defies such simple categorizations as "good" or "bad." I am just amazed because it is such a niche work with a very specific, acquired-taste humor.

But I imagine that the show must be like catnip to ambitious, talented theater folks because it is such a demanding piece that requires its cast and crew to be something like performance decathletes. The on-stage duo and the behind-the-scenes wizards involved in Blackfriars' current production of "Vep" bust their asses bringing to life one of the weirdest shows I have ever witnessed. And their contributions often elevate the intentionally baffling script.

There is honestly no point in recapping the plot of the show. I'm not sure I even could. "Irma Vep" is a ridiculous m�lange of Victorian melodrama, camp, suspense, and who knows what else. The story involves saucy servants, mysterious deaths, werewolves, vampires, and even a motorboating mummy, making it, as one audience member pointed out, a perfect choice for Halloween.

But really, all of the over-the-top trappings are just fodder for the main conceit of the play: two actors portray every character in the show, requiring lightning-quick costume changes and an intense amount of concentration and versatility on the part of the performers. In the Blackfriars production those actors are Ed Popil (as Nicodemus, Lady Enid, Alcazar, and Pev Amri) and Jake Purcell (as Jane, Lord Edgar, and the intruder). The pair of actors creates clearly defined, totally different characters, and attacks each of them with gusto and not even a hint of subtlety. (This play practically exiles subtlety from the first flash of the strobe light.)

Popil may be familiar to local audiences from his recent turn as Max Bialystock in JCC's "The Producers," or as his alter ego, drag performer Kasha Davis. His performance in "Irma" is truly a tour de force, as he switches from a snarling, lusty servant to a fretful former stage star to a tiny wisecracking Egyptian guide. Again and again Popil proves himself to be a clever, intuitive performer, making the most of the show's puns and arch humor. He's also a gifted physical comedian, milking his pratfalls and grand dramatic gestures. My one note of criticism is that Popil throws himself a bit too much into Nicodemus's thick "downstairs" accent, as nearly half of the servant's lines were impossible to understand.

Purcell holds his own in the show, especially nailing the stuffy, forlorn Lord Edgar. In the talkback session after the performance I attended, Purcell explained the cinematic and literary references he used to inform his characters, as well as the way he altered his physicality for each role (grand silent-movie gestures for Edgar, close jittery movements for Jane). That level of thoughtfulness was evident throughout his performance.

The talkback session also revealed that the script allows for the cast and crew of each production to add their own spin to the show, through the staging of the open-ended chase sequences, fights, etc. It is a credit to the Blackfriars group that the best parts of this production are elements it added. Modern pop-culture references, audience interaction, and some smart slapstick sequences helped to liven up what was intermittently a languorous first act that didn't really come to life until the bizarre-but-too-brief trip to Egypt.

This show requires a strong and inventive backstage crew to pull off all the tricks. The costumes and sets designed by John Haldoupis are filled with interesting details (and in the case of the costumes, lots of Velcro) that surprise and charm. Director Danny Hoskins mixes in a variety of recognizable sound cues to go along with the creaky floors. And special credit to dressers Donna Accorso and Sue Accorso, who helped to transform the actors in literally seconds.

As referenced earlier, the show's unique brand of humor will not be appreciated by everyone. My advice: don't bother trying to follow the plot (it's fairly pointless anyway) and instead focus on the superlative theater craft going on both behind and in front of the set. How they pull it all off so seamlessly is a mystery unto itself.

"The Mystery of Irma Vep"

Through November 12

Blackfriars Theatre, 795 E. Main St.

$17-$27 | 454-1260, bftix.com