John Edwards will be appearing in SF, at a low-dollar early-afternoon event -- tickets are $15, and can be purchased at the door. He's still in first place in Iowa, and in contention in South Carolina; if you want a chance to meet the guy who might be the next president, this is as good as it gets. And you really can talk to him; there'll be a crowd for the speech (and the Q&A if there is one, which there was at the San Jose version of this event), but a lot of people meekly disperse afterwards; one of the big secrets of politics is that you can meet just about anybody if you're assertive, and just walk up to the stage after a speech and say something like, "Hi, I'm $name and I really appreciated your point on $topic, but I wished you'd had more time to discuss $other_topic." Campaign managers hate this -- it's why politicians are always late -- but the candidates love it.
I can't make it, because I have a conference call I need to tune into at that time, but I encourage others to check it out.