When you park your hybrid car at this hotel in Washington's fashionable West End, you'll receive a free dessert. But sweet treats aren't the only way the Fairmont melds spoiling its guests with greening the planet. Our favorite effort: the three honeybee hives (home to more than 100,000 Italian honeybees) on the rooftop, which contribute to the restaurant menu as well as the repopulating of this species. Along with the usual recycling and water conservation programs, the hotel provides incentives for staff to use public transportation, works with a local school on Earth Day cleanup, contributes food from its buffet lines to shelters and soup kitchens and offsets all of its energy use with renewable energy credits.