My all time favorite thing to do, on a warm evening in San Francisco:  Walk to the top of Bernal Hill, where people mill about, throwing balls for dogs of all shapes and sizes.

Hike to the top. past the rocky slope, to the grassy side.  To sit with a friend and a bottle of red wine.  Watching the sun go down over Downtown and the Mission.  The sky turning various shades of blues and magentas, while the city lights slowly come up, emitting a warm glow.
One of many reasons why I love this city.