Once, in a two-hour exam, I finished very early so I decided to lay my head down and close my eyes for a while.
I fell asleep. Usually, people just sit still when asleep. Nope, not me. Not only had I been violently rocking and nodding my head, the teacher stopped class for everyone to see for 5 minutes as she made jokes. What woke me? The intense laughter followed by embarrassment.