DURING FINALS LAST WINTER at Northeastern University in Boston, students blew off steam playing Guitar Hero, producing the video game's juice with a pedal-powered generator. Macalester College in St. Paul, Minnesota, handed incoming freshmen energy-saving compact fluorescent lightbulbs along with their campus IDs. And collegians nationwide turned down thermostats; performed waste audits; and lobbied their schools to reduce energy use, provide healthier and organic food, and set a sustainable example for the rest of the world.

Many young people see environmental problems—especially global warming—as the challenge of their generation, and 400 college and university presidents have responded by signing a pledge to make their institutions carbon neutral. Students at almost 600 U.S. and Canadian schools are organizing around clean-energy solutions as part of the Campus Climate Challenge, a two-year-old campaign initiated by youth environmental groups (including the Sierra Student Coalition) that has added sass and sex appeal to a somber topic.

Along with condoms, student educators are passing out CFLs and sponsoring candlelit "Do It in the Dark" events. At the New School in New York City, an "I [Heart] Slutty Paper" campaign helped convince the college to switch from virgin paper (get it?) to 100 percent recycled stock in all campus computer labs. At both party schools and evangelical universities, competitions between dorms, Greek houses, and neighboring campuses to reduce energy and water use are yielding more than just bragging rights: The winning residence hall at Mount Allison University in Sackville, New Brunswick, for example, received an energy-efficient flat-screen TV.

The RecycleMania competition has been pitting colleges against each other for six years, with this year's grand champion, California State University San Marcos, recycling nearly 60 percent of its waste. Even MTV has gotten into the act, anointing student groups at Cornell and Rutgers Universities winners of its Break the Addiction Challenge for their climate-friendly campus activism.

All of this activity made picking our top ten U.S. campuses inspiring and exhausting. For Sierra's first such survey, we looked at everything from colleges' clean-energy purchases and green-building policies to their bike facilities and the food served in their dorms. We checked out how many victories their Campus Climate Challenge group had won and whether organizations such as the Association for the Advancement of Sustainability in Higher Education or the Sustainable Endowments Institute had lauded their efforts. Since the five schools in the Eco League consortium are explicitly dedicated to environmental education, it didn't seem fair to include them in the ranking (there goes half our list!), but it wouldn't have been right to ignore their fine efforts either. To reflect the range of initiatives, we've also highlighted bright ideas and innovative approaches—and a few duds—at other campuses. And we've identified some of the green careers these crusading students might pursue after graduation.

As the biggest purchasers and employers in many communities, colleges can create demand for ecofriendly services and products. High-profile schools have a bully pulpit—and the financial resources—to lead by example with their actions and investments. Research institutions are primed to develop technological solutions. And even small community colleges are educating tomorrow's leaders. If students start their adult lives in a culture of sustainability, they just might take that ethos with them wherever they go. —Jennifer Hattam