Actualy what works real good as a tazer of sorts is using a disposable camera. You wire up the flash mechanism to handle the charge and BZZZT. I think there are some videos floating around on how to do this. It's not the most painful shock, but it definitely wakes you up.

Though admittedly, not as much as accidentally zapping myself with 120v did. Or touching the wrong components when reassembling power supplies (got wrong information by my supervisor)...