A few hours ago I went trough the third Google job interview. In many ways it was very similar to the second one - the difficulty level was almost the same, the questions were similar in nature and detail. The only problem is that I stumbled twice on this interview. First of all I needed a tiny reminder to do a bit of strace'ing before diving into source to debug a problem. However that was tiny compared to the fact that could not remember some details about the physical layout of a file system, specifically the structure of inodes was a bit under my radar.
I must say that I am really enjoying the questions - deep, insightful and satisfyingly complex. It is a pleasure to see my knowledge (or lack of it, sometimes) exposed in a professional way. :)
Many have asked me what to expect from a Google job interview. I must say - expect good questions. Ask yourself, if you would need to uncover as much of your relevant knowledge over a phone line, how would you do it? Expect factual questions about powers of two, programming algorithms and data structures, learn everything that goes on on all OSI levels, practise debugging problems, be inquisitive.
You can only be a true geek if you always want to know how exactly every thing works. You are a true geek, when you do know and understand it. You are a true hacker, when you can use it to your advantage.
If you are a true hacker, then you will have no problems on the interviews.
(Just being a geek also might just cut it ;))

P.S. I tried to follow the latest meme, but according to Google, I need nothing. I wish it was so :D