Ask HN: Advice for a CTO Visiting Silicon Valley

As the CTO of a small European startup, I will have the opportunity to fly to Silicon Valley (San Mateo) next week. I have a free day, and I’d love to immerse myself in the tech/startup atmosphere—not for business networking, but rather to fulfill a childhood dream.

Could you recommend any must-see places? Where can I find information about open tech events? Are there any startups where you can just walk in from the street and drop by for a coffee?