As conventional wisdom would have it, city governments are usually too calcified by stubbornness and bureaucracy to really change the world. But, together with nonprofits and activists, many American cities have imagined novel ways to reduce pollution and help make society more sustainable. Here’s a look at a few places, from New York and Los Angeles to Anchorage and Braddock, that have found creative ways to tidy up their corners of the world.

1. Braddock, PA: Home of America’s Coolest Mayor: At a hulking 6’11”, 340 lbs., with a shaved head, tattoos and biker-gang facial hair, John Fetterman does not look like a politician. But in 2005, the economically decimated rust-belt hamlet of Braddock, an eastern suburb of Pittsburgh, elected him mayor. By one vote. Fetterman has since become something of an international urban development celebrity, using his own funds to repurpose abandoned buildings and throwing his ample weight behind carbon caps and green technology, which he believes will eventually revitalize the town’s workforce. Because of Fetterman, many progressives have fled big cities to join the Braddock Renaissance.

2. Seattle, WA: Letting Goats Do the Dirty Work: The land of coffee and drizzle has been recognized by the National Resources Defense Council as the “greenest city” in the States. Over 90 percent of its power comes from hydroelectric plants. But even around these stations, berries and shrubs grow that are toxic to most living things, except goats. So Seattle puts the hoofed scavengers on grazing duty, and everyone wins.

3. San Francisco, CA: Veggies on the Mayor’s Lawn: Before Barack and Michelle spawned the White House garden, San Francisco’s famously progressive mayor, Gavin Newsom, was a powerful spokesman for the urban gardening movement. Along with the over 17 percent of the city classified as “green space,” the Newsom Administration and the nonprofit group Garden for the Environment have established edible gardens all over the city. That includes City Hall’s front lawn, which every summer transforms into a vegetable patch.

4. Portland, OR: The Yellow Bike Program: Starting in 1994, environmental activists in P-Town released America’s first “community bikes” into the streets. Basically, if you saw one of them (painted road-sign yellow), you could ride it to your destination and leave it there for someone else to claim. The program was a huge PR success, but eventually deteriorated at the hands of theft and vandalism. Since then, similar programs have been floated in Portland and elsewhere, but none have been nearly as simple or as radical.

5. Boston, MA: Taking Back the Trash: Beantown has big plans for its refuse. Currently, it has blueprints for a plant that would turn 50,000 tons of leaves and yard clippings into municipal power and fertilizer, harnessing the power of anaerobic bacteria. Future plans also include creating power from household garbage. Now, if they could wrangle enough goats to clean up Fenway Park.

6. Chicago, IL: Taking It to the Roof: Mayor Richard M. Daley is, without a doubt, controversial. But, if Chicago's recycling program has remained experimental at best, the City With Big Shoulders has excelled in at least one area on Da Mare’s watch: rooftop gardens. Chicago has 2.5 million feet of them—more than all other American cities combined—including one atop the building everyone in Chicago still calls the Sears Tower. The best view of the Windy City may well be from a helicopter.

7. Fort Collins, CO: Cleaning Up With ZILCH Loans: Credit is tight in America, but not necessarily in Fort Collins, Colorado, home of Colorado State University and the Balloon Boy, and consistently ranked among Money magazine’s “best places to live.” Fort Collins provides zero-interest “ZILCH” loans for sustainability-minded home-improvement projects, including solar heating, water efficiency upgrades and high-efficiency washing machine installation. Even for a lefty college town, Fort Collins walks the progressive walk.

8. Anchorage, AK: The Frontier By Moonlight: Like the rest of Alaska, Anchorage spends much of the year buried in snow. And, as anyone who’s braved an Alaskan winter knows, when the moonlight hits the white stuff, it’s practically as bright as day. Thus, during the winter, Anchorage dims its streetlights, letting its citizens find their way around the way nature intended. It also boasts dozens of parks and even a halfway decent public transit system.

9. Oakland, CA: Not the Usual Public Transportation: Like its neighbor across the water, the O relies heavily on mass transit, and has initiated one of the most ambitious bus programs in the country. Oakland is slowly replacing its fleet with hydrogen-powered buses, each of which spares the city 130 tons of carbon-dioxide emissions annually. To boost the new fleet’s street cred, the city runs the buses on special, highly visible routes.

10. New York, NY: Harnessing the Tide: We’ve all heard of deriving power from the force of the winds. But what about the ocean? It’s got some muscle behind it, so why isn’t it pitching in? In New York City, it might soon be. In an area of the East River off-limits to large vessels, the city is currently testing “tidal turbines,” 16-foot rotors that will, if the experiment works as planned, power a supermarket and garage.

11. Boulder, CO: Earth Hour Happy Hour: The World Wildlife Fund’s “Earth Hour” experiment, a polite suggestion that businesses and households turn off all electric power for one hour on the last Saturday in March, hasn’t been around for long. But denizens of the crunchy college town of Boulder already take it pretty seriously. The city officially participates, along with four others in Colorado. And local businesses provide candlelit happy hours with live music.

12. Los Angeles, CA: Keeping the River Alive: LA is not a noted hub of environmental progressivism. The once-mighty Los Angeles River, which runs from the San Fernando Valley to Long Beach and was once the city’s largest water supply, is now 80 percent paved, often runs in a trickle and endures as little more than a punchline. But the ambitious nonprofit Friends of the Los Angeles River (http://folar.org) wants to change all that. Beyond staging cleanups and fighting to hold the city and county accountable for the river’s health, the group aims to eventually bring back clean water, wildlife, and even canoeing. Say what you will: LA dreams big.