Timeline:
In-Person Interview: A pretty standard affair with 5 45-minute interviews and a lunch after the first 2. Most of the people seemed genuinely interested in the interview (save 1 person who seemed annoyed at having to do such a menial task) and were a lot of fun to talk to. I can't go into too much detail on the questions themselves (covered by NDA), but it's standard fare and if you know your stuff, you won't have any trouble.
How to Prepare:
Just brush up on your algorithm design (iterative/recursive algs, big-o, etc.). It might be helpful to just read up on some really clever algorithms from your academic days since the thought processes for those can have a lot in common with algorithms you might be asked to design.
Culture: The people who interviewed me seemed intelligent and very happy to be working at Google. One surprising factor for me was that every single person answered, "What's your favorite part of working at Google?" the same way: "the people."
The following metrics were computed from 748 interview experiences for the Google Software Engineer role in Mountain View, California.
Google's interview process for their Software Engineer roles in Mountain View, California is very selective, failing most engineers who go through it.
Candidates reported having very good feelings for Google's Software Engineer interview process in Mountain View, California.