San Jose, CA, long known as the heart of Silicon Valley, is doing some pretty cool stuff when it comes to sustainability. Within 15 years, the city plans on creating 25,000 clean tech jobs, reducing per capita energy use by 50%, getting 100% of its electricity from clean sources, and tons more! Check it out.
green city
San Jose, CA Leading the Country in Sustainable City Living

United Arab Emirates Vows to Build Greenest City in the World
The United Arab Emirates has begun building what it calls the world's first zero-carbon city. The city will be powered mainly by solar energy and recycling waste and water. The UAE currently has the world's largest ecological footprint per capita.
Masdar: World's First Zero-Carbon City
Masdar City, the world first zero-carbon city, will look strikingly different from today's urban hubs. There will be no sky scrapers or cars. Instead, the city will consist of low-rises lined with solar panels to take advantage of the near-constant sunshine. It's 50,000 residents will move around the 2.4 square miles of the city a series of transport pods which function much like horizontal elevators.

World’s First Eco-Municipality, Boasts Freiburg, Germany
Big push for renewable energy, plus preserving their long history. The Black Forest town calls itself “the California of Germany.â€