If you mean in terms of injury-
When I was about 6-7, I was sleeping on my top bunk. Rolled over the ~1 ft guard rail and fell the 6 feet down and smashed my thumb on the concrete floor (we didnt have the carput put in yet). Thumb was broken.
If you mean in terms of humiliation-
Just this Monday, oh boy... Every year the gym classes at our school go bowling for a week. It was our week. So, I'm bowling right? I'm doing pretty ****** but I'm having fun. Our asshat of a gym teacher tells us we need to start getting ready. Its ok, we had just finished our game. So I switch back to my shoes, classic Adidas-white with three black stripes, and my bowling partner tells me I have one more frame left. So I get up there right, and I start going. Plant my final foot, and it simply sticks, no sliding whatsover. My other leg is already sliding on the toe around the back, and all my momentum is heading foward. I fall flat on my face, and slid probably 5 feet on that oily as hell alley. *Sigh*