I've been wanting to make this project for some time and I have finallly been able to get my hands on the right type of gas lighter to pull apart!
Now this thing won't knock you down but It will give you a good old shock - especially if you hack it and add a bit more power to it.
This is a really easy project which anyone with a little soldering skills can make. All you really need is a "continuous piezo electric sparker" which takes a battery. These are used to light gas BBQ's, heaters, etc and can be purchased from Amazon or Ebay. (see link in step 1)
Remember to be careful - it is electricity afterall and I don't won't anyone to hurt themselves!
Saying that, there is nothing bettter than to zap your brother on the arse and watch him jump!
Check out the video below