Tibetan Singing Bowls
I recently acquired a Tibetan Singing Bowl (well I think it might actually be Nepalese). These bowls, composed of an alloy of six metals, have been used for thousands of years in meditative practices as well as for medicinal applications such as aiding digestion.
How the bowls produce their characteristic singing tone is very interesting. The basic physics of the bowl is covered in the video below, and I think a multi-disciplinary (science, music, culture) study of Tibetan Singing Bowls would be fun and revealing.