Started out with an online tests, multiple choice logic type stuff. Given the operational semantics of a made up language what would a legal operation look like. After that was a phone interview with a very nice person from HR. Then went in for a full day of interviews. There were about 40 of us there and we each had 6 interviews with different people throughout the day. Two asked fairly basic technical questions but most asked questions about my experience and past projects. After that I was asked to come back in for one more interview but from what I understand that is unusual. They also said that it's possible that the CEO might ask for a meeting with you before offering you a job but that wasn't my experience.