This instructable will give you a general discription on how to turn a G-2 pen into an office supplies cannon to annoy classmates or co-workers! It's very simple, takes only about a minute, and shoots your pen part quite a ways.
DISCLAMER: I am not responsible if you hurt someone with this. Please use common sense, and don't shoot anyone in the eyes or face.
Step 1: Materials
This cannon requires very few materials. you will need:
G-2 ballpoint ink pen (yes it does have to be a G-2)
Maybe a paperclip
Step 2: Take Apart the Pen
The first step it to take the pen apart into it's components. unscrew the end, and take out the ink cartridge. set it aside, because you will need it later.
Step 3: Get the Internal Parts: Step One
Next you will need to get the internal parts. take the part that has the grippy on it and invert it and wack it on something hard. the spring should come out easily, but if it does not, simply extract it with a bent paperclip.
Step 4: Getting the Internals: Step Two
Now you will need to take the other end, the one that has the clicky part, and push it out using your ink cartridge to get it out. Two parts should fall out the end, a short, fat one with a little stick on the end followed by the part that you click, the long, skinny one.
Step 5: Assembling the Cannon
Next you will need to take the long, skinny part and put it back in the tube first. (note: you are using the longest part of the tube, not the one with the grippy). it should stick out the end and look almost like it normally would. Next, put in the spring, followed by the short, fat piece that came out first when you took it apart. Now, take your ink cartridge and push down on it until it clicks, and shouldn't come back up. you are now loaded.
Step 6: Fireing Your Cannon
Now take the pen and point it at your target. All you have to do now is simply click the pen just as if you where doing it normally to send pen parts flying! but be carefull, if you don't recover the parts you will not be able to put the pen back together. That is why it is generally best to do it with an old used up pen, like I did.