Last year's Mission District Sunday Streets event was easily my favorite. There's a real qualitative difference between a long, beautiful, but sparsely activated route like the Embarcadero or Great Highway, and this path through a dense residential neighborhood. The former gives bicyclists a chance to ride free from cars, but the latter makes one big pedestrian plaza out of two of the neighborhood's main commercial drags.
This year's event is bigger than ever, with the addition of Harrison Street to the car-free lineup and a later end time: 3pm. Read more at the Sunday Streets website.