If you haven't already experienced the FM3 Buddha Machine this review from popmatters.com sums it up:
The Buddha Machine, then, is a little plastic box that plays music. Specifically, FM3 constructed nine drones, varying from two seconds to 42 seconds, which repeat endlessly in the listener's ear until the "track" is switched to the next drone (or the two AA batteries run out). The machine has its own built-in speaker, in case one would like to fill a room with the drones, but there is also a headphone jack for more personal meditative experiences. There's a switch on the side that allows for traversal of the tracks, and a DC jack (though an adapter is not included) for those who would like the Buddha Machine experience be truly endless. In a way, it's like the cheapest pre-loaded IPod you'll ever be able to buy. It even comes in a number of different colors, for the fashion-conscious experimental music aficionado.
If you're like me and this sounds awesome but you're unlikely to actually buy it, check out the Zendesk Buddha Machine Wall. I turn this thing on at work whenever public radio starts talking about musicals and serenity soon follows. It's great with tea.
There's also an iphone app.