After talking to a recruiter at a university job fair, I received an email requesting me to take a plant tour. The interview was conducted during the entire tour. It was very laid back, and didn't include any type of "personality" questions. The tour did include another candidate; there is potential for the interview to feel competitive, although, in my situation, we were applying for two different jobs. There was a good deal of sarcasm during the day; I think it was used to weed out anyone who was too uptight. Make sure you can take a joke, and just have fun during the interview.