A flame burning inside an upright pipe near the lower end of the pipe creates a pleasing musical note at the resonant frequency of the pipe. I first tried this with a length of metal downpipe and a gas stove with the flame spreader removed, after reading about it somewhere. If you assemble a collection of pipes of different lengths (just like a set of ordinary organ pipes) with a burner and pilot light in each one, and link the valve controls of the burners to the appropriate key on a keyboard (easy - switches in electronic keyboard connected to servo relays on valves) then you have a flame organ. So far, pretty much baked, but without the keyboard interface: _see link_ OK, now you mount one of these where the burner sits in a hot air balloon, and start playing. Manic evil laughter optional. For best visual effect, use heat-resistant quartz glass pipes, and inject metallic salts flame spectrophotometer style for chromatic scales. Like, I can see the music.