AKA Going Ballistic On A Bike.
I had to try the fixie craze, so I bought one on Amazon. Under $150 delivered, it weighs probably twice what my mountain bike does. I rode it around with the flip-flop hub allowing it to freewheel, so it was just a single speed, then I tried it fixed.
It was pretty good toolin' around my neighborhood, so I took it a little farther afield. Got heading down a really good hill, spinning like mad, and there are speed humps on this road. First few went OK, as I kept telling myself not to level the pedals and bunny-hop over them.
I forgot on the last one. I leveled the pedals.
Let me explain that. I stopped pedaling and set my legs rigidly. However, the wheel continued spinning. Therefore, so did the pedals, at roughly 1/3 the speed of light. That meant that I was slammed by the upward-rising back pedal, firing me into the air at the aforementioned 1/3 of lightspeed.
This would have been entertaining by itself, as I became a ballistic object, but there's another factor. I had clips and straps on the bike, so my feet were affixed to the pedals. As I started on my ballistic path, then, the bike came with me.
I wish someone had had a camera handy, as I feel like I flew over that speed hump at an altitude sufficient to read on air traffic control screens. However, what goes up must come down, and by this point, I had no control whatsoever over the events unfolding. That is how I happened to come down upon my bike's saddle, bending the seat post in the process. Somewhere in the sequence of events, my feet came out of the pedals. What was left of the seat amazingly supported my weight, the pedals were whirling like a propeller, and I held my legs out to the sides so the pedals wouldn't chop them off. As the road sloped up, I finally slowed, and stepped off onto a curb.
I looked around, but didn't see any dumbstruck onlookers to bow to. I hobbled around a little bit (I had, after all, crashed down on the seat quite... sensitively), then took out my tool kit and got to repairing the seat enough to get home.
When I got home, the FIRST thing I did was flip the back wheel to the freewheel side.
Never again will I ride a fixie.