You can't squeeze blood from a stone, but you can get sound out of sand dunes. Singing dunes often make sound on their own, as a result of spontaneously coordinated avalanches of sand, according to a paper recently featured in Physics News Update.
What I hadn't realized is that people can effectively play the dunes by pushing sand to create their own avalanches. The researchers who studied the sounds of the dunes collected some videos of people scooting down dunes to make tones, and posted the clips on their (poorly designed) web page. They also built the apparatus shown above to make their own sand sounds.