I know, I know, it’s an ad, but it’s a damn cool ad.
I linked to this a while ago, the excellent "Thru You" remix project.
The project was bouncing around my head recently and reminded me of these "OS Sounds turn into music" compositions as well. So I spent some time youtubing it up and pulled out quite a few good ones.
From the Conservatory of Flowers in Golden Gate Park. There is a really awesome Butterfly exhibit there.