I've done some self-bondage techniques with electricity that come very close to being out of control but not really. Take a look at my recent post here:

http://www.bdsmlibrary.com/forums/showthread.php?t=2567

If was to start doing this again, I would probably use some kind of computer interface and put some randomness into the length and intensity of the session so I would not really know for certain what i was getting into. that would add a bit of additional excitement.