In the personality interview there were lots of the thought provoking questions like, "tell me about a time you failed at something", or " tell me about a time you had to do something you disagreed with." The technical interview stayed pretty high level, but that's probably because I answered the initial questions fairly well. There were a few points where the topics went beyond my skillset, but I just answered honestly that I didn't know and that worked well.

Lets just say the interview process requires some on demand mental math which isnt difficult until you factor in a group of people starring at you intensely until you solve it or give up.