I made this gun bored at work. you can get the materials anywhere and its very easy to build. it can shot up to 2 rubber bands on the same shot. :D
Step 1: The Shape!!
This is what I use for the main frame of the gun. its a rope holder that I have found in my office. You can use anything with a similar form.
Step 2: Main Cannon.
Well as you can see there main cannon is a stick with some tape fixed into the main frame. Just put a plastic seal or some plastic tape to put it into place. Up to this its made with essential things!!
Step 3: The Trigger
The trigger (if you can name it that way) it's an office clamp fitted with a plastic seal. Just put a bolt inside the clamp hole and the trigger will be ready
Step 4: Gun Holder and Aim
aim is made of a piece of plastic left by the plastic seal. make little cut on the cannon just to fit the front part of the rubber band there.
Step 5: Add Some Paint!!! Time to Have Fun!!