first go buy the works toiletbowl cleaner
image ^^
and aluminum foil
if you dont know what that is then dont look at this tutorial
and a bottle (preferably a Gatorade bottle)
now wad the aluminum foil up into little balls
about 5 should do
and put them into the bottle
now pour the works in the bottle
get the liquid level just over the top of the aluminum balls
shake 2x and run like hell
it should explode in about 1 minute
if you want to see one in action go to media/videos and watch the one i made go off