Twice.
1 - was coming home via bike in 8th grade. Front week locked up going down a steep hill and I flew over the handlebars and landed on my head, then slid for several feet. An ambluence came and took me to the hospital. Luckily no concussion or brain damage, my helmet had absorbed the impact and exploded into several pieces. Severe roadrash on my face and arms. Was out of school for a week healing up. It sucked real bad changing bandages.
2 - Gallstones. Halloween night 2012. I was eating KFC and drinking beer with my best friend. Suddenly I felt intense pain under my right ribcage. Started throwing up. My friend rushed me to the ER. Got some morphine, which is about the most beautiful substance in the world. Got some ultrasounds. Doctor gave me my diagnosis and said it needed to be removed, but since I didn't have insurence at the time, he wrote me a prescription of XXL Tylenol and called it a day.