Make:

N3ldan sent in his homemade cheap capacitor bank and recharger, he writes - "Here's how to make a capacitor bank useful for many applications, ie a railgun, coilgun, RFID zapper, for $0~50 depeneding on what tools you have and how fancy you want the final product." - Link.

Always be careful with these sorts of things of course.

Related capacitor projects:

• Camera Coil-Gun - Link.
• PowerLabs Electromagnetic Weapons! - Link.
• DIY RFID-Zapper... - Link.
• HOW TO - Make a RFID-Zapper - Link.
• Build a RFID reader/capturer/cloner - Link.
• The Railgun Blog, building a home made railgun... - Link.
• Supercapacitor contest! - Link.