Here's how to make a really cool launcher out of a spring pen.
Step 1: Step One
Before you begin, the only pen hat works is the type of pen I'm using, so you'll have to get one of these types. First, you have to take it all apart. The tip is tricky, and I suggest using a skewer to get it off.
Step 2: Step Two
Slide the ink cartridge through the tip, and then slide it through the top of the pen.
Step 3: Step Three
Place the spring on the little knob thing, and then slide it in the bottom of the pen, knob thing side first.
Step 4: Step 4
Screw the clicking part onto the pen. It's okay if the tip pops out, just put it back on, nice and tight.
Step 5: Step 5
Now, you can launch the pen! To reload, just put the ink cartridge and the tip back in and fire away!