Cat's whisker diodes and the initial discovery of the LED are other good examples of this. Connect a small wire to the right kind of rock (or rusty old razor blade) just right and you get a diode. If you get it just perfect (and use the right kind of rock) you'll even get a faint LED.
Indeed! That brought back a vivid childhood memory of moving the cat's whisker around on a crystal to find just the right spot to pick up the local radio station.
It was mind-blowing to realize that the acoustic waves vibrating my eardrums were directly powered by the radio waves transmitted from the broadcast antenna.
