Happened when I was 7 or 8, my parents bought a bunk bed for my sister and I, but they told us not to climb to the top bunk ourselves just yet (can't remember why we weren't using it yet). Being rebellious children my sister and I climbed up the ladder to the top bunk, and was caught by my dad. Because I was the older sibling my father made me stay on the top bunk (there was no mattress, just the wooden frame). I stayed there for around 5 hours till midnight in a locked room in complete darkness, until my mum came home. Didn't dare to move until she returned because I was that afraid of my dad. There were more painful punishments but this probably was the worst