3 of them.
1. When I was 6 or something, I wanted to play Hide and Seek with my parents. I was dipping my hands in some juice, didn't know what it was. I was the seeker, so I covered my face, and figured out that I was dipping my hands in Jalapeño juice.
2. I was 10 and playing tackle football with my friends. One of them had the ball, so I tried to tackle him. I was about to land on him, but he managed to turn around and land on me with his back. I ended up springing my arm.
3. I had pectus excavatum this year. Pectus Excavatum is the result of having a bar put in across your chest, under your ribs to straighten them out and uncave your chest (yes, my chest was caved in). When I woke up.... you can figure out the rest yourself.
... I guess I'll post one more.
When I was young, me and my niece (who's strangely a year older than me) wanted to land on our beds with our backs first. Our beds were really a sheet, blanket, and pillow on the floor since someone was spending the night. I landed on my back, and man that hurt so much.