There are quite a few ambient sound generators out there -- what's special about this one is that there are almost no parameters to mess with, and instead you load a "set" of sounds, and users can submit new sound sets to the website, which are pretty coool.
from http://www.all4you.dk/FreewareWorld
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Sound Borb is an audio ambience generating system. The generative nature of Sound Borb's audio engine means that once you hit play, the ambience you're listening to will never end. It will never go to the next track. It will never loop. If you want to listen to the ocean, you can listen to the ocean from now until your electricity goes out. Various ambiences are available for download on the download page, and you can also create your own and post them for download here, if you're so inclined.
Parameters are kept to a minimum, so as to make Sound Borb easy to use. Just load an ambience, and start listening. You can adjust the overall volume, the intensity (how much activity is occuring in the sound), and the happiness of the ambience. Or you can set the intensity and happiness parameters to auto, and sit back and listen.
from http://www.all4you.dk/FreewareWorld