Jaltarang, one of the world's most obscure musical instruments, is a collection of 16 bowls filled with varying amounts of water that are struck with sticks. It's sound is delicate, but rhythmically propulsive. Really quite lovely.
Indian tabla percussion-driven ragas are commonly performed on jaltarang, but so are Indonesian influenced gamelon-style sounds. I can't really figure out where it comes from, actually - it's so ancient, we may never know.
India's Milind Tulankar is one of the few virtuosos still playing jaltarang and has a number of cds but, fittingly for such an esoteric tradition, I'll be darned if I can figure out how to order them. At least he provides a number of samples and video clips on his "Sounds" page. Listen to:
Puriya Kalyan: Exciting, fast, hypnotic; and that tabla player's going nuts...