If the goal is to relax and "absorb" tech culture, I'd go with everyone else's suggestions. Tech-focused cafes include Creamery, SightGlass, Philz, and The Grove in SOMA. If you have a car, driving around Sand Hill (not in SF) and visiting Rosewood will definitely give you the opportunity to tech eves-drop.

If you'd like to meet some real entrepreneurs, engineers, designers, investors in the trenches, download our app (www.weavenow.us). There are thousands of people you can meet in SF if they're also interested in meeting you.