DENVER -- On Thursday, Colorado Gov. Bill Ritter will be in Washington testifying before Congress on global warming. The governor will also participate in a discussion on "the greening of America."

Many Colorado companies are leading the way in those efforts to save the planet. Two Colorado companies in particular are making bold environmentally conscious moves.

The newest star at Metro taxi is the Toyota Prius hybrid.

"I'm (driving) along and little kids are waving," said Prius driver/owner Pamela Martinez.

It's quite possibly one of the most visible signs of efforts by Colorado companies to save the planet.

"These new hybrids are super fuel-efficient," said Metro Taxi sustainable resources manager Chris Cotter.

Metro now has 10 Toyota Prius hybrids, changing gears after 30 years with cars by Ford and Chevrolet.

"They weren't getting there in the fuel-efficiency category. And we wanted to do our part to help out Denver's air quality," said Cotter. "Toyota puts in billions of dollars to the American economy every year. And they build a huge (percentage) of their fleet in North America."

"This car's completely different. It's quiet," said Martinez, comparing it to her old taxi. For Martinez, the hybrid is the driving force behind her decision to stay with Metro Taxi.

"I get anywhere from 43.8 to 54 miles per gallon. I have many regulars because of it. It's been an incredible move. There's no doubt about it," said Martinez.

In Steamboat Springs, Big Agnes outdoor gear is unveiling its latest planet-friendly product -- a sleeping bag that saves space in the landfills.

"It's made out of recycled plastic bottles," said Big Agnes owner Bill Gamber.

In fact, the zipper is the only part of the bag that isn't recycled, and they're working on that.

"If the outdoors aren't clean, and people are getting outside, our industry's done," said Gamber, who also lives in a home that operates exclusively by solar power.

Inspiration for the sleeping bag came when Backpacker Magazine challenged pack manufacturers to make a backpack as green as possible.

"We wanted to stay ahead of that and so we thought it was a real challenge to us to design a sleeping bag that was recycled," said Gamber.

Big Agnes also rewards employees who bike to work with points toward vacation or products.

"And then you bring that home and you start to think, 'How can I reduce my impact in life?'" said Big Agnes employee Piper Watson.

At Metro Taxi, they're even using used motor oil from their cars to heat the maintenance shop.

As for the car, it is not only saving the planet, but drivers' pocketbooks.

"In one week, I spend maybe $60 in gas. I was spending that a day in the Crown Victoria," said Martinez.

It's a bit smaller, but you'd be surprised. When you get in, they're ergonomically fit quite well," said Cotter of the space in the Prius.

Metro Taxi said the car makes people smile, and it even appears to smile back.

"I get waved at when I'm driving, like I'm in a parade," said Martinez.

"This is going to be our new flag and we're gonna fly it high. Green and white," said Cotter, referring to the cars' color. The white paint with green lettering is a departure from the company colors of white, orange and blue.

Metro Taxi managers said their dream scenario calls for switching the entire fleet -- 500-plus vehicles -- to all hybrids. They say that could save 3 million gallons of gas every year.