Google

I had 6 or 7 interviewers in a row, and they all asked algorithmic questions, school-book style. Nothing about my past experience was discussed; all the questions were puzzle-like, covering topics such as sorting, lookup, hashing, and multi-threading

The recruiter who contacted me was very helpful. She described to me how the interview would be, what to expect, what not to expect, and what the interviewers were looking for, pretty well without a single hint of any question. She did her job well.

The onsite interview process consists of four rounds, each approximately one hour long. Two rounds are scheduled for the morning and two for the afternoon. At noon, a Google employee will take you to lunch and chat with you.