From Habr:
When I was a child, I almost feared my grandmother in the village.
During the summer holidays, he wrapped 30 meters of wires between trees, made a simple contour and grounding, and connected all this to a high volume dynamic. During the day, it was heard so to yourself, if you lean closer - the words could be disassembled, but at night... I reasoned that once the receiver is not powered by the network or the battery, it can not be turned off. As a result, at night the whole house was raised to the ears, because the Germans cried loudly in the room!