From Just Food:

Solar One presents Citysol 2007, a clean energy, interactive art and music festival that aims to celebrate and inspire local sustainability initiatives. The event takes place from July 12-15 (Thursday to Sunday), at 23rd St. and the East River. If you have to choose, pick a weekend day - you can enjoy good music on a solar and biodiesel powered stage, along with a green product marketplace, games and workshops. Bring your electric bill, change to a renewable source for electricity and receive a free beer from Brooklyn Brewery! For more info and a detailed schedule, visit the Citysol site at Solar1.