My first post is going to be about making a pen launcher. Its really easy to make.
You need: a bic pen, and a balloon (don't blow it up!)
1. First get the bic pen, and see that thing at the bottom, well pick that out (it should be pretty easy)
2. Once you have the bottom thing out (if you couldn't get it out you either have the wrong pen, or you need to man up) take the pen part out.
3. So now you should have a pen tube, a pen, and a balloon. Next put the balloon on one end of the pen tube and put the pen in the pen tube.
4. Then pull back on the balloon and the pen should shoot out.