We have had multiple sessions, ranging from technical ones such as distributed version control systems to more political ones such as how to deal with assholes in open source projects. There were lots of passionate people in these talks, and it was quite interesting to see it all. The cool thing, though, as opposed to other conferences, is that everyone here comes from a different project and background, so you get to see lots of different opinions and points of views for each topic.
As regards the Google HQ campus, it is great. I thought the NYC offices were good, but these are spectacular to see. Unfortunately, there is not much to do out of them... so I'm not sure if it could be so good to work here for a long time.
Now, I'm sitting in the San Jose airport (SJC) waiting for the flight back to NYC. Amazingly, there is free internet wireless connection and electrical plugs! Very, very nice detail. And there is few people around, which makes it very quiet and relaxed.
Oh, and to those who will decipher this: some more mini golf training during the summit :P