The mouth harp, also known as the Jew's harp (despite having no connection to Jews) or jaw harp, is one of the weirdest musical instruments. How many instruments do you know of that depend on the vibrations of the musician's skull to be heard? According to Wikipedia, the instrument dates back to at least the third century B.C., but the source they cite is just some guy's blog, so who knows. My friend Dennis not only owns a mouth harp, but he knows how to play it! Here's a video of a little jam session we had with my father, me, Dennis, and Merle on my trip to the States in February. I came up with a couple chords, strummed a rhythm, and Dennis – and his vibrating skull – matched the notes exactly. My celebration at the end is rather exuberant, but there was plenty of wine flowing and the performance really was quite awesome.
I recommend watching it larger. This video is also available on YouTube, Yahoo, Metacafe, Google, Break, DailyMotion, Blip.tv, Veoh, Imeem, Stupid Videos and Viddler.
Thanks to John White for the video.