Some of my favorite community gardens in San Francisco are smack in the middle of the street.
Quesada Gardens in the Bayview is the spectacularly beautiful result of what happened when neighbors who were afraid to walk out their front doors got the nerve to plant a garden in the middle of their street. Now they are a tight-knit community of friends and Quesada Avenue is one of the city's loveliest streets. They also painted a mural on the median's retaining wall and show movies at night there for the whole neighborhood. Kudos to Jeffrey Betcher and the gang at Quesada Gardens Initiative for their devotion to this exquisite site.
I've been watching the plantings along San Jose/Guerrero winding up the median over the last couple years and wondering when they'll make it all the way to Market Street (I bet they do eventually). The San Jose Guerrero Coalition to Save our Streets is responsible for this one and I lovelovelove it. Gillian Gillett and her neighbors grew tired of living on a quasi-freeway and are attempting to calm the traffic, and succeeding, with help from Flora Grubb, DPW and donors of plants, $$ and labor. As the winter rains come you can see the plants staggering back to life (they're natives so don't always look colorful and showy, duh).