I really didn't know what to expect before the season hit. I have to say that my experience has been totally benign. I interviewed at 17 programs, and never had a bad experience.
Most places want to just feel you out. I was rarely asked medschool type questions. If they did ask questions, it was usually personal- girlfriend, where are you from, etc. I concentrated on the east coast, especially NYC. I think these places really want to know why you are interested in the specific hospital. Many, many programs in NYC, with rare exception I found them to be similar. These programs interview about 100 people for say 5 spots, they want to know how serious you are about the program.
Some non-personal questions that did come up:
explain a cholecystectomy to me as if I were your patient, and not a doctor. (an excellent question, in my opinion)
Tell me about an interesting case...
(I would anticipate this question, and be REALLY prepared about the topic. Look it up before the interview season begins).
"We are on rounds, and I tell you to give lasix to a patient who I think is 'wet,' and leave rounds. You remember thinking that she was 'dry' and needed fluid on pre-rounds. No attendings or residents are available, what do you do?"
I heard of somebody being asked to demonstrate a one-handed and two-handed tie, left and right handed. Also to draw an anastamosis for a pancreatic surgery the candidate had seen, with blood supply and drainage. These questions are exceedingly rare in my experience.
I think I was asked "so what questions do you have for me" on every interview, so be prepared to ask questions- good questions - on all interviews (even if you already know the answer)... just pick 4-5 really good questions, and ask them in some way on every interview.
All in all, a pretty benign experience unless you are an idiot. As long as you wear the right suit, don't spill breakfast down you shirt, and are on time you pass that part. Otherwise, I think the program directors just want to know:
1. Can I work with this guy/girl for 5-7 yrs
2. Why does this applicant here- any indication that this applicant will rank the program higher than the other applicant with same board scores, etc.
Good luck!
