Hey,
It'll probably vary from college to college, but I was given about.. 20 lines or so of text in the interview itself and given a few minutes to look at it (plenty of time). The questions I think started generally with a 'tell me about any interesting features' or similar, but he was very quick to prompt me if I got stuck - it turned into a proper discussion rather than a hard-fire question session. Hope that helps, feel free to pm me if you've more questions!
H