What should I get up to in SF?

I'll be in SF for a family wedding next month, and I'd like to get a feel for this much touted startup thing.

I'm looking for opportunities to network, meet some interesting firms, and generally take in the vibe. I already have a couple of introductions, but I figured the startup thing is so big there, there must be some kind of event you can just show up to.

I'm currently on the job market, but I don't have a US visa, and I'm most keen on remote work. My main experience is in building trading systems in financial markets, but I also build websites and apps for iOS and Android. If I can pick up some freelance work, that could be cool.

My brother is graduating with a CS degree this year, from an Ivy league institution. He'll be looking for grad jobs. Is that something you can just show up and arrange some interviews for?