How do you make a simple shock stapler (or shock pen) similar to those found in joke (prank) shops or how do you make a very simple small shocking device which produces a small shock using just a 1.5v battery? What are the parts required and why does a shock pen contain a transformer?
Far be it for me to advocate not making something and buying it instead, but you can buy these from eBay for $0.01. After you have one I'd bust out the Dremel and try integrating it into various other devices.
Also, and I'm speculating here, the transformer is probably to step up the voltage at the expense of current so that it's somewhat painful. A taser works in a somewhat similar fashion.
1.5V is not enough voltage to feel as an electric shock because your skin has a high electrical resistance. Therefore you have to increase the voltage before it can be felt. Tranformers are the most common way to convert between different voltage levels. That's why a shock pen has a transformer in it.
the problem with hooking a battery directly to a transformer however, is that a transformer requires a constantly changing magnetic field in it's coils to function correctly, which a battery cannot provide.
So an intermediate circuit is necessary to convert the constant voltage of a battery to a pulsed signal. There are many ways of accomplishing this. Just do a search for "high voltage schematic" or something along those lines.
here is one example result I found members.misty.com/don/hvinvert.htm