"What's the fastest way to become a commercial space millionaire? Start as a commercial space billionaire." So goes the joke in the space industry, and some billionaires are putting this theory to the test, as I covered in "Just For Fun: The New Space Race." But if you are missing the billions and just want some inexpensive rocket fun, then consider a more earth-bound air-powered paper rocket.

It would appear that flying devices and paper are intimately linked, and here again is more proof of that. I came across the plans for an air-powered paper rocket. Its environmentally-friendly fuel - air - is safe and readily available. The rocket can be fueled up and launched indoors with minimal safety requirements according to the instructions:

• Put the launch pad onto a robust and unbreakable surface!
• Remove all sharp or pointed object around the pad!
• Keep the airspace above the pad free from all faces!

Feeling competitive? Then compare your flight data with other pioneers on the plan's website.

For the seriously competitive, why not try out your modifications in the virtual world first by simulating the rocket with your favorite Computational Fluid Dynamics (CFD) tool.