In some ways, for the intrepid, 50-year-old San Francisco Mime Troupe, the more things change, the more they stay the same. Year after year, there is a hot-button social-political issue du jour, and every year the Troupe puts its leftist, satirical-musical spin on that issue, creating a new work to be presented in parks in the summer. The Troupers--a collective of artists who can hammer a nail as well as transform themselves into comically exaggerated, singing characters--conceive the plays in a process that can be at times rambunctious. This summer's musical, "Too Big to Fail,"a parable in the African folktale idiom, premieres at Dolores Park on July 4. At a rehearsal two weeks before the first preview, in the Troupe's rambling old building in the Mission District, the end of the play had yet to be written, but the story was firmly in place. When villagers Filije (Adrian Mejia) and Jeneebal (longtime collective member Velina Brown) marry, a local witch makes Filije an offer he can't refuse: a low-interest loan against the dowry, which is a goat. But fees are involved, and the goat is repossessed. Filije embarks upon a quest--confronted along the way by animals and menacing humanoids--to cancel the debt and reclaim the goat. A griot, or storyteller, narrates; he's played by Michael Gene Sullivan, head writer since 2000, when longtime head writer Joan Holden departed. As the collective tossed around a few ideas for this year's show, the topic of banking emerged as a no-brainer. They broke it down further to focus on the flawed concept of credit. But the goal is broader: how, they wondered, to make audiences truly question the notion of capitalism per se? When Sullivan proposed framing the satire as an African folktale--deconstructing it mythologically, with a hapless young couple, magic spells and ruthless demons to personify the ideas--the concept began to take shape. Sullivan read African folktales about the griot tradition--"I wanted to give it that feeling, not just make it a Mime Troupe show with kinte cloth"--and co-wrote the script with Ellen Callas. "Part of the show is about how this couple finds out how to work together as a team," he explains. "We're always trying to make our work about real issues, so the couple is trying to make choices." The rehearsal room reflects the Troupe's hodge-podge style. Shelves overflow with outsized, hand-made masks, boxes of stuff with scribbled labels: "Women's vintage hats." Buckets of paint lie around the periphery. Stuffing sprouts out of old furniture. A large mannequin sits in a corner. Director Wilma Bonet, who acted with the Troupe in the '80s and has returned to direct, is rehearsing a scene with Sullivan and Mejia in careful, minute detail. Another cast member, BW Gonzalez, is out sick today. Veteran Trouper Ed Holmes peruses the "New York Times," and actor Lisa Hori-Garcia, in a brimmed hat and tailored jacket ransacked from the wardrobe, practices gestures in front of a mirror. "There's a different vibe here now," Bonet says later, at the lunch break. "It feels calmer. I've gotten calmer over the years. I've learned, as an actor and director, things always come together in the end." She points to other changes since she last worked here: professional designers (in the past, collective members took on those jobs), interns helping out, and, for the first time this year, body mics. Back when Bonet performed here, there were no mics at all, and actors co-opted the wind to carry their voices. Over its five decades, the Mime Troupe--founded by R.G. Davis originally as a project of the old Actors' Workshop--has experimented with various genres. Some of Davis' earliest productions were indeed silent (although not pantomime). Later, Davis produced outdoor shows, classics adapted to satirize contemporary political problems and performed as Italian commedia dell'arte, a broad style of physical comedy featuring stock characters in masks. When Davis left in 1970, the Troupe reformed as a collective and settled mainly on melodrama as its format of choice. Always the Mime Troupe has stuck to a radical political agenda, challenging audiences to think as well as to laugh. It has won three Obie Awards and a Tony Award for Excellence in Regional Theater. "I studied the Mime Troupe as an undergraduate!" exclaims 28-year-old Mejia. He arrived last year to teach a youth workshop. "Wilma is one of the actors in the documentary Troupers [about the Mime Troupe]. Now I'm being directed by this woman who I saw perform and be interviewed!" He is bemused by the irony. "There are books out about this company--and here I am trying to find a coffee filter so I can make coffee." If Mejia is the newest, and one of the youngest, in this year's show, Holmes (known for playing "the cheesy white guy," as he says) represents the old guard, with the Troupe since 1986 and as committed as ever. This summer, Holmes plays a variety of characters, from a tribal chief to a roaring lion. "It's still the same chaotic process," he says, of the collective's group decision-making. "We still have to argue about the theme of the show. Sometimes everybody has a different agenda. We finally settle." But he sees changes, too: The troupe can no longer afford to tour to far-flung places (in the past, shows have played in Jerusalem, Cuba and elsewhere) or to formulate five-year plans. "We're lucky if we have a one-year plan," says Holmes. Notes Sullivan, who joined the company in 1988, "Every once in a while people will say, 'You guys aren't cutting-edge anymore. You used to always get arrested.'" But the country itself, he points out, has shifted since those early days. The Mime Troupe may not get busted anymore, but, says Sullivan, "It's our job to stay on things that still need to be changed." In the rehearsal room, the actors gather around the piano with musical director Pat Moran, who wrote the songs and lyrics (at performances, Moran and two other musicians will provide live accompaniment). "Ain't nothin' more to life than makin', makin' money," they chorus. The assistant stage manager wanders past, snapping a rubber prop knife. Hori-Garcia's ancient dog, Flower, jumps on a chair. "It's not just about work, it's community. It's family," comments Mejia. "There aren't so many models of artist-run organizations that are really sticking to what they're trying to do as well as evolving from one generation to the next." Says Holmes, "I'm lucky to be involved. It's a unique organization and a unique style of theater that couldn't exist anywhere but in San Francisco, because of the mental weather and the physical weather. This is a place of aggressive thought and experimentation." He adds, "We're still trying to find the thing that's in the zeitgeist of the moment, and bring a radical interpretation of it. That stays the same." "Too Big to Fail," July 4-Sept. 27, free in Bay Area parks. 285-1717. www.sfmt.org