not that most of this falls into any of the above catergories really but rather just completely insane, but I've just been reminded of Jeff Mangum's legendary WFMU radio shows and they're completely insane. field recordings, bulgarian music from 1927, half an hour of yodelling, ETC.
obviously its massively inconsistent but such an interesting listen. Think i've amassed about 2GB and only listened through everything once.
torrenting's probably your best bet but I can probably find some still-active links floating about if anyone's interested