I mentioned this in another thread, but's an example of something that deserves a thread of its own.

An organ played by the random movement of the waves: The Zadar sea organ

A lot of us will have windchimes. A friend of mine has made a couple of Aeolian harps - they were quite popular in Britain the 18th century. There are quite a few instrument/sculptures where the "player" is a force of nature, or something with no human intention behind it.

The most extraordinary one I've heard of was set up in the beaches on Micronesia to guide the souls of the dead on their way to the next world. It was a collection of full-length bamboos, with a slot cut in each segment at a random point round the circumference. So as the wind changed in strength and direction, it would sound a continually varying clustered chord of flute sounds. I have some of it on an old Ocora LP (Musique de Guadalcanal), but obviously a recording can't convey much of the effect you'd feel standing in a forest of shrieking poles in a storm.

What favourites do people here have?