The event consists of tours of local interest, workshops and panels, the aforementioned business meeting, and the banquet where the Nebulas are awarded. The banquet costs extra, of course. It's a bit like a small convention except that almost everyone there is either a writer, an editor, or an agent.
This year, in addition to the regular Nebulas, Connie Willis was inducted as a Grand Master. It was great to be there for that! Who does not love Connie Willis? I wish I had thought to bring my camera instead of just my phone, so my photos aren't great, but I had a wonderful time, especially at the banquet. The MC was Walter Jon Williams (think overgrown imp) and the speaker was NASA astronaut Mike Fincke (imagine if Bob Newhart had become an astronaut). Also, Neil Gaiman was there because he was nominated for (and won) the Ray bradbury Award for best dramatic presentation for his Dr. Who script of "The Doctor's Wife." SFWA President John Scalzi has a list of the other winners here.
Next year the Nebs are in San Jose. If you're anywhere near there, I recommend it as a fun activity, whether you're in SFWA or not. And if you want to save money, you can attend the awards after the banquet at no extra charge.
Here's a photo I snapped while they were waiting to take the official photos; the rest of mine are here.