Once upon a time, I jumped off a sand dune and landed on my head. I wasn't trying to land on my head, that was just how it happened.
I was on a field trip for strat/sed class. We went out to some dead sand dunes. The professor told us if we ran off the top of the sand dune, jumped, and landed the right way, we could become "one with the sediment flow." I was the shy transfer student who still didn't know anyone because that university's orientation program for transfers was nonexistent and I barely even knew where the geology department was, much less who my classmates were.
So naturally, I thought I'd get into the spirit and jump because everyone else was jumping.
As I'm running towards the end of the sand dune, I start to jump and a classmate's head pops up from where I'm about to hurl myself. I somehow twist in mid-air, tumble, and fall head first onto the bottom half of the sand dune. You know, where the hard part is?
I didn't fall exactly on my head. Had I done so, it would have been far better for me. Instead, I fell on the back of my head and neck, with the full weight of my body coming straight down on top. When I landed, my legs were straight in the air, then pitched forward and I was thrown reverse-somersault down the rest of the dune.
For some reason, I stood up and laughed. Someone asked me if I was okay. I said "sure, fine!" and we finished the rest of the trip.
My neck got increasingly sore on the ride home. I went to bed and when I woke up, it really hurt. I took a handful of Aleve and went about my weekend. On Monday, I woke up late to class. By six hours. The next day, same thing.
After a week of this, I had friends come physically jerk me out of bed. Apparently they had drug me halfway to the living room before I came to. That's when I went to the doctor.
Lots of money and a few CT scans later, no one had any answers. Whatever sleep disorder I had continued for a few more months. I learned to sleep as soon as I got home in the hopes I'd wake up at some point in time for class. The semester did not go well. Eventually, those sleep troubles went away entirely, though I now have insomnia. Wheee.
I did manage to coerce the doctors to give me a copy of my CT scans. For "informational purposes" I told them. In reality, I just wanted a picture of my brain. Because brain pictures are awesome.