I had a very bad one around 8 years ago (back when I was at school). I can't really remember what happened...one minute I was sitting at the computer, the next minute I was in the kitchen with my parents, sitting on the freezer waiting for an ambulance (feeling very nauseous, with a bad headache and lots of carpet burns!). Apparently, my folks heard a loud bang, and my dad came through to find me under the table, fitting. Thought it was epilepsy at first, but tests proved otherwise (and it's not happened again since). After a bit of investigation, we found that the kettle lead for the printer had an illegal plug on it (very small, and had no plastic bits covering half of the pins - got it from a dodgy PC supplier (who doesn't exist any more)). I must've needed to print something, crawled under the table, and accidentally touched the pins while plugging in the printer (with the force of the shock causing me to whack my head on the underside of the table). I'm actually quite glad I don't remember what happened - probably would've scared the crap out of me!