North American workers can learn a lot from their South American counterparts about taking over factories. So says the San Francisco Mime Troupe, and it's offering two object lessons - rolled into one - to illustrate its point.

"Posibilidad," the company's annual free summer musical, opened Sunday before a large crowd at a traditional Independence Day with the Mime Troupe in Dolores Park. The new show provides multiple opportunities to cheer the workers and boo the outsourcing conglomerates and greedy bankers in an agitprop melodrama that takes on the issues of downsizing.

It wouldn't be a Mime Troupe show if it weren't funny as well as politically engaged, and funny about being politically engaged. Michael Gene Sullivan's script and composer Pat Moran's lyrics are packed with satiric zingers about everything from the New Age approach to firing ("I am releasing you to find your bliss") to where to find jobs ("Guarding empty buildings is one of the fastest-growing jobs in America").

But it isn't an upbeat show. Though it has its standard happy ending - a bit forced but heartwarming - "Posibilidad, or Death of the Worker" hasn't yet found its balance between the serious plight of the workers in its California and Argentine story lines and the bright humor of its wide-ranging social satire.

Sullivan's juggling of the stories is awkward at times, as he alternates between the closing Peaceweavers New Age Urban Hempwear plant in this state and an abandoned textile mill in the Posibilidad barrio of Buenos Aires. Director Wilma Bonet lets the action go slack at times, particularly in intercut scenes between the workers' attempts to run the plants as collectives.

But the play's ambition is as impressive as its range, hitting topics as diverse as telenovelas, smarmy eco-marketing, soccer loyalties and the tango. Bonet lights up the stage with some of the Mime Troupe's sharpest choreography in years to Moran's bright tunes. And the cast, led by an appealing Lisa Hori-Garcia - as the immigrant Sofia who ties the stories together - excels in many quick-change parts.

Brian M. Rivera is as brash a Marxist Argentine lover as he is sweetly shy as a Filipino with a crush on Sofia. Velina Brown anchors the show as an awakening Californian and a militant, avid soccer mom. Sullivan delivers an illuminating portrait of labor shortsightedness, while the versatile Rotimi Agbabiaka and Maggie Mason depict diversely villainous capitalists and telenovela lovers.

The message comes through loud and clear in a provocative juxtaposition of different forms of workers' ownership. If "Posibilidad" hasn't yet realized its possibilities, it's already a bold and entertaining attempt.