I believe there were four interview rooms: chairman (get to know you), research, ethics, and fund of knowledge. None were very grueling because it was pretty late in the interview season and I was fairly relaxed by then. If you haven't had a lot of people quiz you, the fund of knowledge section could be a little unsettling. Overall, the guys out there were very nice and relaxed. My perception was that they just want to pull your chain a little bit during the interview to see if you handle yourself well and fit in with them.
