This IS a weapon and it IS dangerous. The blowgun should never be pointed at another person, and be careful where you shoot it. I've had the darts ricochet back towards me several feet on occasion. Also, be careful of pricking your fingers, eyes, etc. while making the darts. Thanks.
Step 2: Materials
Pencils - Staples pencils are cheap
Pushpins - The ones with balls for heads
Yarn - I used red, any color will do
PVC Pipe - about 2 feet of 1/2 inch PVC
Step 3: Tools
Step 4: Step 1
Carefully (without destroying them) pull the metal parts off the pencils.
Step 5: Step 2
Cut the yarn into about 2 1/2 inch pieces. You will need 4 or 5 pieces per dart. The pencils can be thrown away, or sharpened on both ends to look cool.
Step 6: Step 3
Push the pins through the eraser from the metal end. Try to get them to come out as close to the center as possible. Only go in far enough to see the point on the other side.
Step 7: Step 4
One at a time, wrap 4 or 5 pieces of yarn around the pin. The method for wrapping is demonstrated on a pencil so you can see. When you've wrapped the yarn around the pin, push the pin the rest of the way through the eraser.
Step 8: Final Step (Optional)
Download ("http://www.mytargets.com/Target4%20red%20circles.pdf") or draw a target, pin it to a piece of corkboard(bulletin board), and practice your aim.