Have a look at the Flamethrower Ukulele that Caleb Kraft from Make built. Might not be the project that you want to use indoors or around anything flammable that you care about. But if you have a fire extinguisher by your side this sure would be fun to build, if you are an outdoor performer this would double as good crowd control. The system uses a modified calking gun to squeeze a small butane cylinder allowing the gas to flow down a hose to the end of the ukulele neck. A spark ignites the gas and starts the flaming fun.