You have to be a little crazy to tilt at windmills — or sometimes, just to build them.

Meet Michael Reynolds, who has been raising hell and building what he calls earthships in the Taos, N.M., desert for more than three decades. With his long, gray hair, salty language and almost surreal single-mindedness, Reynolds is a larger-than-life man of eco-action.

He believes he is here to save the Earth — if only out of self-interest.

Reynolds is the star of the documentary "Garbage Warrior," which helps open the second season of Sundance's "The Green" — a weekly, Tuesday night block of programming focused on the environment.

And he is a magnetic presence — whether he's building houses out of old tires and bottles, providing shelter for tsunami survivors or battling politicians.

"Garbage Warrior" is many things — a meditation on the need to think outside the box in trying times; a suspenseful yarn about a maverick's struggle with the status quo; and more than anything else, a profile of a visionary who may be carbon neutral, but is neutral in no other sense.

He started out as a classically trained architect at the University of Cincinnati, but he didn't want to build little houses made of ticky-tacky; he wanted to build houses out of beer cans. So he moved to New Mexico, and did just that.

The walls of Reynolds' organic-looking houses are filled with detritus — cans, tires packed with dirt, plastic and glass bottles.

"This is garbage and it comes out like stained-glass jewels," he says, admiring his handiwork.

The walls absorb heat from sunlight in the winter, and insulate against the heat of summer. Windows are strategically placed and modulate sunlight; solar panels and wind turbines generate electricity. Rainwater is captured; wastewater is filtered and reused. Greenhouse areas are used to grow food. The aim is to make the people who live in these houses self-sufficient.

"You can get up in the morning and you own your own life. You don't have to do anything," he says.

People flocked to New Mexico to buy Reynolds' earthships. But he was making it up as he went along, and the experiments sometimes had unhappy results — leaky roofs, too much heat. Once, an unhappy homeowner showed Reynolds his vintage typewriter. It had melted.

Local officials heard the complaints and went after Reynolds and his crew for code violations, shutting him down. He lost his license as an architect. To keep his business going, he had to build more conventional housing, conforming to rules written for Levittownish subdivisions.

"I had lost the freedom to fail," he says.

And so began an epic campaign to persuade the state Legislature to except experimental, sustainable housing from the strictures of normal housing. Reynolds puts on a jacket and tie, pulls back his hair in a neat pony tail, and begins to lobby.

If "Garbage Warrior" has a weakness, it is the nearly total depiction of local and state officials as mindless drones. Some or many of them may be mindless drones, but in fact they are charged with writing and enforcing laws that protect the public health and safety. Perhaps they should be skeptical of Reynolds' rap.

Regardless, the scenes in which images of soaring birds are intercut with others of legislators napping at their desks are a cheap shot.

But the scenes that follow make up for it. Reynolds takes his magic to Asia, to show people left homeless by the 2004 earthquake and tsunami that they can use garbage to build houses. He takes it to Mexico, to help victims of Hurricane Rita in 2005.

The aim is to give these unfortunates shelter, while at the same time exporting Reynolds' new American Dream — a dream of a life in tune with the Earth, a dream of the self-sufficiency he has found.

"I am free," he says. "I am absolutely free."