I was reached out to by their HR, who saw my LinkedIn. She requested a phone call to talk about the opportunity and the recruitment process. At the end of the call, she asked if I wanted to go straight into the first phone interview with her. I wasn't expecting that, but figured I'd go ahead and get it over with. A lot of the questions were around why I made different decisions since high school (from how did you choose your university, how did you choose your major, the groups you were in, the job you took after college). They also asked which office I would want to interview with, as well as the reason for the location (I requested LA).
After that round, I got invited for the person interview. This lasted a full day. Started with a tour of the facility, sitting in on a customer service call, and talking with one of the guys that handles logistics. All of this, I learned later, wasn't actually part of the interview process; those people had no involvement in the hiring decision, and couldn't give their input either. However, you want to be attentive during this whole session, since the interviewers will ask you questions about your thoughts about the departments you saw.
After the tours, it was 4 back-to-back interviews, including one over lunch. Mostly fit questions. One or two case studies based on projects they were currently working on.