We can all dream of what San Francisco might be like if faucets ran with ice cream and Japanese selvage jeans fell from trees. But there's one alluring fantasy we can actually see in real life: major streets opened up for humans, devoid of cars. On several Sundays in spring, summer, and fall, the city creates large, temporary public spaces by closing off a neighborhood's streets to traffic, making way for pedestrians, bicyclists, skaters, dancers, stroller-pushers, and other activities for a few hours. If you can visit only one, try the Bayview on June 12 or the Mission on Oct. 23. There's nothing like a sea of delighted people drifting through streets usually occupied by 2-ton metal death machines.