My older brother made a jacobs ladder while doing an electronics apprenticeship in the navy... For those that dont know a jacobs ladder has 2 probes and will generate an arc between the 2 which will climb up the probes or "ladder" until it breads at the top and starts again at the botom.... anyway. I found this little project while cleaning out the shed one day and decided to hook it up and have a look. It basicallly consisted of a small circuit board with 2 probes off on end, 2 cables with large alligator clips to hook onto a battery and a car ignition coil in the middle.
When I hooked it up I realised that there was a short on the cable that went to the probes... The cable that I was holding! Now unlike a car ignition system this circuit is not designed to switch on and off... It stays on! I was paralyzed by approx 20,000KV running up my arm. It was un-comfortable to say the least and it took me about 15 - 20 seconds to pull the cables off of the battery! It hurt like a bastard and josh was right its like being punched everywhere all at once... In my case for an extended period.