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.
Serendipitous science at its best! Or, how to increase your luck surface area.