Well interviews were really different last year, and the years before that. Earlier there used to be three interviews (if you could call them that)... one interaction with students and then two interviews with faculty and alumni...
This year they have something new planned out and even we aren't sure... though we're getting our jobs assigned sometime this week...
The best advise possible... just be yourself... (Big cliche I know!!) But it works!!
The interviews aren't meant to be too serious and the interviewers will often mess with you a lot!! Best policy, don't budge!! Stick to what you actually believe.
You'll know what I'm talking about after your interview!!