> I couldn't track it down for the longest time, until one night the night
> watchman for my apartment was walking down the hall outside my room (my door
> was open), and then I heard his walkie-talkie (or long-range radio of some
> sort) beep. He then spoke into the walkie talkie/radio, and lo and behold,
> my speakers came to life and rendered a _very_ scratchy rendition of his
> voice - bad enough sound quality that I couldn't make out exactly what he
> was saying, but it was recognizable as being his voice, if you heard both
> him actually talking and the speakers at the same time. =)

I'm far from a wizard in this area, but that sort of action doesn't 
seem all that strange.

The key thing you need in a radio receiver is some non-linear circuit.  
Diodes are great - that's all you need for a crystal set.  Computers 
are full of diodes.  Many chips have free/extra/hidden diodes, especially 
when the input signal is out of the normal range. 

You might be able to solve the problem with standard EMI procedures 
- the math/physics for junk getting out of a system is the same as 
for getting trash in.