Streetsblog SF reports that the Castro will be home to San Francisco's first JSK-style pedestrian space. 17th stree will be closed to cars from Market/Castro east for half a block, as depicted below.
The old-timey F-Market streetcars that stop there will continue to do so, as you can see, but planters and street furniture will prevent cars from accesing the space. This project is being planned as a temporary, trial project, and city officials will study the results closely. No word yet on when we can expect to see this with our own eyes.
News of this project may help folks in North beach who want to close a section of Vallejo street to create a similar pedestrian 'piazza' next to Cafe Trieste. That project is waiting for funding, but Streetsblog commenters aren't the only ones speculating that it could benefit from a trial program similar to the Castro's.