There's actually an Interview Feedback section here on SDN, where you can get all the inside scoop on medical school interviews (i.e. questions asked, length of interview...) at PSU and other schools.
Overall the interview day is pretty laidback. You do two faculty interviews, one M.D. and one Ph.D. My interviews were no longer than 45 minutes each, but it can vary from one interviewer to the next. You tour the school and eat lunch with first and second year medical student (not in this order because you have the option of morning or afternoon interview).