but i sumbled uppon a site with audio/noise samples. and though it could be nice to have some of them playing wiht low volume all the time, or at least when nothign else is hearable.
they are all under the creative commons license, and most of them can be freely used by non-comercial products.
http://www.freesound.org
An example (called "birds in spring"

http://www.freesound.org/samplesViewSingle.php?id=16726
i have never done a widget or gadget or whatever it would be. so i dont have an idea what the possible problems could be with that. and how hard it would be. the songs come in various formats (wav, mp3, ogg, aif, flac, ...) but that should not be a problme, as they could be converted of course.
soo.. please just give some general feedback.
EDIT: hmm.. just though that... using a music gadted that already exists as a base should make it quite easy, hm? :D