My new absolute favorite thing on the web is FreeSound, an archive of Creative Commons-licensed sound files uploaded by users, like an aural version of Flickr's Creative Commons pool. They're tagged with keywords, and some of them (to the delight of someone as map-obsessed as I am) are geotagged so that if you want to hear what a hot spring in Iceland sounds like, you can browse for it on a map of the world.
My first thought, when I found the site, was that this would make a wonderful source of chill-out background sounds. One could download a whole set of sound files of cats purring, or rain falling, or birds singing at dawn, or whatever; assemble them into an album in iTunes; turn on one's computer or plug in one's earphones; and ta-da: instant de-stressification. (I've been working on various solo projects at work that require concentration but still make me want to listen to something in the background. All of the above fit the bill admirably. I especially recommend the cat purrs.)
And my second thought was "Ooh, one of their top recordings is a nightingale singing. Come to think of it, I don't think I've ever heard a nightingale. I've always wondered what all those poets were talking about. Wait a minute — someone should totally put together a set of sound files to go with the Norton Anthology of Poetry! Think of all those students who've never heard a nightingale or don't know what a dulcimer sounds like!" And I still think it's a rather good idea. I mean, imagine the possibilities:
Who else wants to build an open-source multimedia poetry anthology? I think it would be really cool if such a thing existed.