Exact coordinates: 37.769404, -122.511056
No official website, but here's the public invite: https://www.thesamba.com/vw/forum/viewtopic.php?t=615918&start=140&postdays=0&postorder=asc&highlight=
FREE. Just show up! This is a popular event with relatively limited parking. Get there early if you want to guarantee yourself a spot. The event takes place in the parking lot across the street from the Beach Chalet Bistro.