My friend and I had a flame thrower war with spray paint cans and lighters (we were in the 7th grade). It was very short and we both lost.
I built a simple flame cannon a few years go, shoots a 30-40 foot mushroom cloud into the sky if you shoot straight up. Good for clearing the range (culdesac) of unexploded munitions (fireworks duds) on the 4th of July.http://hallert.net/misc/pneumatics/pneumatics.html
When I was 12 my best friends mother wouldn't allow him to play with me anymore after I set him on fire.
Put a +1 on your geekness atribute