What's better than one green business? Five green businesses. And what's better than that? A business devoted to supporting some of the most ethical and innovative green businesses in the East Bay, often five at a time. East Bay Green Tours, housed in the David Brower Center, Berkeley's greenest building, formed in late 2008 as a way to show off the East Bay's emerging green corridor. From there, its vision expanded to themed tours open to the public (organized around themes such as waste, water, energy, and building) and custom tours designed for specific groups (the Oakland Museum of California, Berkeley High School, and Contra Costa Community College have all been clients). Founder Marissa LaMagna has established an impressive, ever-growing network of contacts at local startups like BTTR Ventures, the Emeryville outfit that grows mushrooms in coffee grounds; city departments such as Berkeley Public Works; and corporations such as Waste Management. Her tours offer participants a cohesive and entertaining peek inside the minds of some of the greenest thinkers in the East Bay — and, indeed, the entire country.