High Heat wont work, its proven data can be recovered from burned and thermite'd drives... it must be electric or magnetic in nature, to help rearrange the metal pieces in the magnetic formation. and super high levels of magnetism are quite unattainable unless you happen to work for the DOD ...a defense contractor working on this...comments about their magnetic media destructor...and the serious amount of engineering that went it. Similair magnetic strength to an MRI.... Producing a magnetic field sufficient to destroy data patterns required the use of neodymium iron-boron magnets custom-designed for the project and special pole pieces made of esoteric cobalt alloys. The magnets, which weigh as much as 125 pounds, had to produce fields sufficient to penetrate metallic housings that surround some drives.
You can trigger a similar device automatically based on a pre-occuring event. Much the same way that you would set an alarm, but rather than set off a siren, it will erase your hard drive. Not sure if something like this exists, but at least you won't blow up your house.
On a lighter note, you can also label it "Compilation of Andy Rooney's Random Thoughts" and nobody will ever go near it. I doubt anybody will ever take it this far though...