The judges for moot court can be law professors, attorneys, or members of the judiciary. Judges can ask questions at any time during the presentation, and students must respond. They need to understand the facts of the case, their arguments, and the arguments of the opposing side.
When I sent a card to my husband's moot court partner and his wife on the occasion of their wedding anniversary recently, it reminded me of the agony that led up to the day of the actual arguments, as they reviewed together and prepared for that momentous occasion. (As I thought of it, I was again grateful that my husband had encountered this young man on the first day of law school, because he taught him how to study, something he had never needed to do in high school, and didn't do much of in college.) I think it was their last year of law school; it seemed to be gathered up with finals and graduation practice and even a little bit of spring fever. I went with my father-in-law and the father of my husband's partner and my memories are all gray: it was evening, the room seemed dark where the arguments were presented and my recollection is that every man was wearing a gray suit. I had given up my gray nun dress so I was probably the only spot of color there.
I don't remember if it was a competition, as many moot courts are, but I am fairly sure that they were told that they had done well, because we all went out to dinner together afterwards, the fathers congratulating the sons and everyone in a benevolent mood. It was one more milestone on the way to my husband becoming a real lawyer. His coolness as he delivered his arguments and answered questions was a good predictor of his performance as a litigator after he passed the Bar Exam and started working at a law firm, when it seemed as if real life had finally begun!