You can count on precious few things these days – but in a sea of change, you can still cling to one sturdy and inescapable fact: Tim Miller will wind up naked if he’s doing a solo show. In “Us,” Mr. Miller’s hyperactive assault on anti-gay legislation, he keeps his end of the bargain.

But even with his shorts in a pile on the floor, Mr. Miller’s strip-tease for understanding doesn’t push much beyond the usual boundaries for one-man shows – it never manages to surmount its own gimmick.

Mr. Miller, a groundbreaking activist/actor/monologist, co-founded P.S. 122 in 1979 and racked up controversy as a member of the “NEA 4.” He returns to his P.S. 122 stomping ground (anointed, he assures us, by two and half decades of sex in the wings) to kick off their 25th Anniversary season.

Part of the “out and loud” movement, Mr. Miller has a talent for injecting humor into the most earnest rants and cheerfully violating taboos. Unfortunately the theatrical unsteadiness of this performance, its jerky rhythms and occasionally hokey sentimentality, fails to involve the uninitiated.

“Us” has only one memorable image: a flag made from Broadway posters, “Gypsy” white, “Oliver” blue, and “Hair” red. Mr. Miller would have this be our national symbol – one for “us,” not simply the U.S. Politically, Mr. Miller can convince us to pledge allegiance to his cause. But theatrically, this sort of one-man show is hard to salute.

There is no slow build to Mr. Miller’s work – he starts out with the accelerator on the floor. An Ethel Merman disco re-mix still pumping, he’s already gasping from exertion when he enters in stretchy black shorts and gym shoes with a prop suitcase. He wants us to feel his frantic hurry, because he him self is being given the bum-rush by U.S. immigration. U.S. law refuses to issue same-sex partners green cards, and with his Australian lover’s visa expiring in a month, Mr. Miller must choose between a partner of 10 years and exile. He has already started to pack.

Into the suitcase go the things that he cherished growing up gay in California – memories of grade-school plays, some particularly titillating National Geographics, and a stack of Broadway cast albums. In the funniest segment of the show, he imparts the lessons he’s learned from those records: “1776” taught him about governmental hypocrisy, “The Sound of Music” taught him to leave organized religion for love, and “Oliver” gave him a lifelong penchant for English accents and floppy boy fringe. But “Gypsy” left the deepest imprint of all. Thirty years later, Tim Miller still wants to be a stripper, seeking bravery and self-realization simply by exposing himself.

***

While Tim Miller is taking off his shirt to make a point, the musicians at St. Ann’s are doing it to survive. In “Decasia,” a creepy total-environment take on “Fantasia,” the orchestra sits on scaffolding, completely surrounding the audience. Baked by theatrical lighting and a dozen projectors, the steaming TACTUS Contemporary Ensemble saws and bangs away at Michael Gordon’s alarming new composition from their positions high in the air. When the shirtless percussionist behind you starts whaling on a huge drum, his sweaty effort becomes part of the piece – which in turn is primitively exciting.

“Decasia” is a collaboration between Mr. Gordon, filmmaker Bill Morrison, and the Ridge Theater. Ridge’s director Bob McGrath and set designer Jim Findlay envelop the audience with images by swathing the surrounding scaffolding in a scrim that works as a partially transparent projection surface. While we can just see the musicians behind them, the “walls” also glow with Laurie Olinder’s still images (usually tile patterns or geometric theorems) and Mr. Morrison’s film.

Mr. Morrison’s black and white “nitrate distressed” film splices together an infinite variety of ancient, decaying images. Even without the nitrate erosion, this would be haunting: in one scene a parade of Louise Brooksbobbed schoolgirls walk past two waiting nuns. But with the fungus-like patterns of decay exploding around them, the girls seem to be marching silently through a blitz, turning to smile through gunfire.

The musicians themselves bring new meaning to the term “surround sound.” The instruments at different pitches and staggered rhythms create an out-of-control and off-balance experience. Though the piece doesn’t quite sustain its crescendo for the entire 64 minutes – any sensory overload wears off eventually – it’s the closest thing to the adrenaline of a horror film you’ll find that far downtown