One of my best friends didn't take heed of my "don't touch the fucking circuit board inside the PSU" comment one night. His PSU fan had stopped working and he tried to replace it.
That was awesome
His arm turned red
I myself have been shocked by a LAN card once, but that's as far as it goes. Nothing too serious (computer related).
I did, however, grab a plug from the wall and my index finger and thumb slipped past the plastic and ran along the metal prongs (as they were still plugged into the wall a bit) and I almost fell over in pain. My arm BURNED for an hour.