I would guess relatively less weight would be placed on the interview when compared for example, to the statement of purpose. The structure of the interview allows only 20 seconds to prepare a minute response, which makes it seem more like an exercise to see how an applicant thinks on their feet rather than a way to gain substantial insight into their abilities or motivations.
Personally, I did it yesterday, and one of my 3 questions was, "If you could have dinner with any 2 people, living or not, who would they be and why?" My other 2 actually came from the pool of those listed in other comments above. Best of luck if you choose to take it!