Every once in a while, something begins as a curiosity, then becomes an event and ends up an institution. Martha Graham Cracker, the drag diva who croons and swoons, toys gleefully with an audience and is glorious in all her imperfection, will never be the sort of institution with a huge mandate, like the Philadelphia Museum of Art. But she performs there.

She also performs to packed houses at Joe's Pub, a part of the Public Theater in downtown Manhattan. And on Broad Street at the Pennsylvania Academy of the Fine Arts. Big deals, all of them, but Martha's home stage is down-home, indeed: L'Etage, an upstairs bar and performance space on Bainbridge near Sixth Street, where 150 or so people jam the intimate room monthly to watch a cabaret that is flirty, highly musical and all for fun.

On Thursday night at L'Etage, the drag queen and her band celebrated eight years of kooky, and maybe kinky, performances. Ms. Cracker's singing has become substantially better over that time (this was my fourth look at her), and her mostly improvised two hours, more well-polished. That said, the show still feels, thankfully, as if everyone's just come together by chance.

She's got a great band — the Philadelphia Magazine "Philly Post" blogger Victor Fiorillo on keyboards, with Andrew Nelson, Ned Sonstein, Ernest Stuart and Rich Hill, respectively on bass, drums, trombone and guitar. Thursday night, vocalist Christie Parker provided back-up on several numbers. And the cabaret features other guest musicians.

Martha's patter has a stand-up comic's timing, her moves are deliberate and showy, and her persona, air-tight. Her presence is large: Martha is 6-foot-2 barefoot, 6-foot-7 in heels.

The best joke in all this — to me, anyway — is the identity of Martha Graham Cracker's alter ego, the accomplished actor Dito Van Reigersberg. He's among the founders of the Philly-based Pig Iron Theatre Company and remains instrumental there while balancing two distinct but related professional lives, one in platform high heels, purposely ill-fitting vinyl and an assortment of wigs, and another as a busy actor and teacher.

I first saw Martha, by chance, on the opening night of the 2007 Philadelphia Live Arts/Fringe festival, now called FringeArts. I arrived at the Fringe bar — an after-hours club set up for the run of the festival — fresh from a Pig Iron premiere of "Isabella," a re-worked production of Shakespeare's "Measure for Measure" but set in a morgue where the actors, playing the dead and often without clothes, gave a mostly monotonal reading of the Bard's play. Van Reigersberg was one of them. About 45 minutes later, a mile away, I walked into the Fringe bar to find a warm and unexpected sight: a woman who was clearly a guy in a gown — blue, I think — singing her heart out to an audience cheering her on.

It was Van Reigersberg again, as Martha, an act he'd been performing here and there for two years, refining all the way. Naked and reciting Shakespeare one minute. In a gown belting torch songs the next. I knew the Fringe had begun.

At the 8th Anniversary Show on Thursday, it was clear that Van Reigersberg's Martha works so well because she remains on the fringe. Van Reigersberg — who studied briefly at the real Martha Graham's dance school and, like the other Pig Iron founders, is a Swarthmore alum — has called Martha an example of "monster drag," meaning she's clearly a man parading as a woman and not intending to be mistaken as one. Van Reigersberg is hirsute and so is Martha, a part of her in-your-face charm. His black short-cropped hair often peeks out from her blond wig. And while Van Reigersberg has a generous vocal range, Martha's speaking voice is at only a slightly higher pitch than Van Reigersberg's.

Martha's act is a mix of medleys, or songs with dramatic arrangements; her "Don't Cry for Me, Argentina" was a jazzy number with a dramatic effect and by the time she hit "God Only Knows" in the second half, the crowd was into every nuance of her delivery. Alcohol helps in this, but I don't think it was the compelling reason that the audience was in her sway. For one thing, there's the aura of the act and its history in the city (that's the institution part). Also, there's the attraction of Martha's constant jab at being glam and what that may or may not mean. And mainly, there's Van Reigersberg himself, an intelligent and bold actor, bringing all his talent to bear yet succeeding without a real script. 

Some of it is priceless in person. On how to do Tina Turner: "You have to pretend that your feet are running away with the rest of your body," which Martha proceeds to demonstrate — and prove. On her stage relationship with singer Johnny Showcase, who opened the evening: "We'd like to get married but also permanently divorced." To the straight people in the audience, and there were apparently many, in couples: "Whoever is straight here, I don't care. Just remember, you were born that way — it's not a choice."

Van Reigersberg, at 40, said recently on WHYY's "Friday Arts" television program that he may be getting old for this. (Not that Martha's indeterminate age seems to shift.) And Thursday night's charged show, ending around 11:30, left me wondering whether poor Martha will have to sleep in 'til lunchtime the next day. But I don't think Van Reigersberg will have much of an aging problem, not as long as Martha herself doesn't. Alter egos have a funny way of taking over, I suspect.

The Martha Graham Cracker Cabaret is at Johnny Brenda's (1201 Frankford Ave.) on August 31; at L'Etage (Bainbridge near Sixth Street) on Sept. 12 and Oct. 10 (with a special show featuring the band Sept. 22); at the Pa. Academy of the Fine Arts on Oct. 3; and at Joe's Pub in New York on Oct. 26.