Are you kidding me? Disposable camera flash? That's... startling. No more than that.
What the OP's wife needs is a Leyden jar.
And, of course, a way to charge it. She can even fill it with jelly beans or something. There are very few things that I work with regularly that I have as much respect for. Charged with a van de graaff generator that's at least at 80kV, they can pack one hell of a wallop. I was holding a charged one in one hand while opening a door with the other hand. I accidentally brought my opposite arm near enough to the electrode at the top that I got knocked on my ass. And, by knocked on my ass, I mean I literally went down to the floor from the shock. I've grabbed an electric fence 20 yards away from a 40 mile fence charger, and accidentally grabbed a steel fence gate with my opposite arm as it swung shut, completing the circuit (I was insulated from the ground.) That sucked. That sucked really bad. But, I'd rather do that again a dozen times in a row than get nailed by that Leyden jar again.
p.s. I'm more or less kidding about the Leyden jar - the larger ones can be fatal. This spark is wimpy compared to some of the ones that I've made:
http://www.youtube.com/watch?v=f6_ADvpW0CA
Once it's charged up, it makes a great demo to students why you don't open things that say "warning, danger of electric shock, do not open" - even if they're unplugged. (Unless you're quite certain about what you're doing.)