take a sobe glass bottle, fill it 3/4 full with gasoline, set it on a fire until the fuel begins to boil, then take a knife or srewdriver a poke a hole on/in the top of the cap. once the air hits the burning gas the fuel ignites and shoots a flame straight up about 15 feet high for a good minute.
ive never done it myself but watched a guy do it out at dumont in the camp next to us. it seemed pretty cool but appeared a bit dangerous!!!