TheBackyardScientist is behind some of the most interesting videos we have seen lately. His latest video shows you how to create an awesome propane rifle. You are going to need a self-igniting propane torch and 10 feet of 7/8″ tubing to get started. When the button is halfway pressed, the torch sends a combination of propane and air into the tube. Press the button all the way, and a flame is sent flying through the tube.
As you can see in the above video, you can have a lot of fun with a propane rifle like this. As always, you may want to use some caution when trying projects like this.