When I was going to NAIT the kids in electronic engineering set up a display for their open house exhibit: they wired up a toilet seat to a rheostat and ran a couple amps through it. Visitors to their booth were invited to sit on it and were told exactly what would happen - and the contest was on! Most people jumped off after an amp or two but a couple of the hard rocks redlined it at 4A.
Something like this, juiced up to about 6A
oughtta do it.
Mind you, there's some people out there that once their ego is involved - you could probably light 'em up and fry 'em and they still wouldn't get off. I could see it being a profitable and interesting social experiment.