I got a portable shortwave radio the other day at a flea market. It's really a pretty good one. Some of the stuff you receive on it is pretty fringe. Last night I picked up what's called a "numbers station" which was a woman reading numbers in Spanish. Those broadcasts are very common and widely known to be encoded messages for spies. Very freaky stuff. There are examples of lots of short wave weirdness on youtube if you want to hear.