Back in the late 80s, I had a 1964 Ford Fairlane (my first car) and I was putting in an Accel Supercoil to replace the old girl's dead factory unit. I was busy tuning the engine, and setting the timing on that little 260 v8, when I made my first mistake. I got careless, and managed to get my fingers whacked with that old steel fixed fan. I was so horrified I couldn't even look at my hand for a minute - I was sure I was missing two of them. I could hear my dad's voice playing inside my head, saying things like, "Ever notice how many old mechanics are missing fingers? That's because of metal fan blades and belts." Thankfully, I must've gotten smacked by the blunt part of the fan, and I just had some nasty bruising. My fingers were still there, and even though they hurt like hell, they still worked.
So, after getting over the excitement of that mishap, I wanted to turn off my engine, since I was done setting the timing anyway. Instead of taking the time to get out of my car and turn off the key, I had a brilliant idea:
Why not pull the center lead out of the distributor, so it stops the ignition?
So, kneeling on my chrome bumper in a pair of shorts, and holding onto my brass radiator with the other hand, I pulled off the center plug. Now I know most of you understand a bit about electricity. Your spark leads provide a strong positive charge that wants to go to ground (negative charge), and it will find the fastest, easiest route to do so. My skinny little teenage body was the perfect conduit for all that fire from the new Supercoil (which could jump a half-inch gap as I recall). By the time that engine stopped spinning, sending sparks through me, and died, I nearly did too. If my math's right, I ate somewhere between 50-100 sparks from that big old coil, as the motor wound down. What I can tell you is that I'm pretty sure my heart stopped and restarted quite a few times during the experience, and I was shaky for many hours afterward, not just from adrenaline!
So lessons learned: Don't stick your hand in the path of a steel fan, and don't ever grab the center ignition lead on a V8.