Slightly tangential story. My first assignment on my first job was building a knockoff TEMPEST enclosure (http://www.jammed.com/~jwa/tempest.html) to isolate spectrum measurement equipment. The original use of the enclosures was (somewhat ironically given the article) the NSA's paranoia that foreign intelligence would spy on government computers by picking up their EM radiation.

So if you're worried about the government spying on your computers via RF and want something more convenient than a fridge, drop me a line...