I have a few,
First, when i went to do a flip on my trampoline, went off the edge and had my head going for the ground, at 4 inches from the ground i managed to flip enough so it was my back that hit, still hurt like hell.
Umm, when i was at my friends house and he threw me off his second story balcony in his living room(A weird one), i landed on a couch though
When i was in the bathroom, and it was 3am so it was really dark, i opened the door to walk out and my mom was standing there, i flipped stuff and jumped back 3 feet, because it was dark and she just stood there, she didnt say anything.
I was playing L4D2 at my friends house on April Fools day, and he startled a witch on purpose, after killing him it came after me, the second it touched me he had his sister, who was dressed up as a which, jump on me and start slashing, i was like FUUUUUUUUUUUUUUUUUUUUUUUUUUUU UUUUUUUUUUUUUUU-
When i was out in the lake with my dad and uncle on our boat, we were about 3 miles from land on every side, and i jumped out of the boat to piss, then he turned it on when i was right behind it, freaking the stuff out of me, and drove away, btw i can't swim well enough, 100 meters and i am out of breath about to drop.