A friend indicates that garbage bag full of acetylene, detonated at night, can attract the attention of sheriff's deputies from a real long distance. Said friend is from Texas, and has a graduate degree in hard sciences...who do we know like that?
It appears that calcium carbide cannons are still available to the general public:
http://www.cannon-mania.com/bigbang.htmCalcium carbide reacts with water to from acetylene, useful for ripening fruit, powering a miner's lamp, and desulfurizing iron (?), and quoting wikipedia, "it is still used in the Netherlands and Belgium for a traditional custom called Carbidschieten (Shooting Carbide). To create an explosion, carbide and water are put in a milk churn with a lid. Ignition is usually done with a torch. Some villages in the Netherlands fire multiple milk churns in a row as a New Year's Eve tradition. The old tradition comes from the old pagan religion to chase off spirits."
I'm getting some for my BOB.