Mine come from various endeavours.
...Like one time, I was splitting wood with a chisel wedge and a 20 lb. sledgehammer. Hit a knot going sideways in the wood, and the wedge came flying back at me. I thought I had gotten out of the way ok, but when I looked down at my leg, I saw that I hadn't. The doctors said a millimeter deeper and I would've had to have reconstructive surgery to repair the muscle, and 1/2 cm. in either direction, and I'd be dead. Got way too lucky.
...Also broke my back on a waverunner when I was 18, but that's another story.