I think I had HI in class once. My teacher was lecturing about something and I was drifting in and out of consciusness. All of the sudden I see my teacher riding backwards on a horse going away from me, still giving the lecture. It was awsome!

Maybe because the chairs in school are so uncomfortable that you cant actually get into a deep sleep, so you remain in a sort of limbo. Constantly gaining and losing conscious could make you get close to dreams but keep you aware (basically WILD). Just a thought.