Ask HN: Where to find a potential co-founder?

I know that this might seem like the wrong question to ask. You are supposed to know your co-founder very well by the time you start a company together. But most of the people whom I know from college are not willing to take the risk of starting a company on their own. It's hard to persuade a risk-averse person to become an entrepreneur, and even if I am able to persuade him, some months down the road when the going gets tough, he might be tempted to chicken out.

So what are some of the events and groups in the Bay Area that provide good opportunities for meeting potential co-founders? Thanks.