Audio stuff

http://aporee.org/
The largest online audio map, to which anyone who wants can upload their field recordings.

http://listen.hatnote.com/#en
Listen to the sound of Wikipedia's recent changes feed.

http://www.michaelgallagher.co.uk/how-to/starting-out-with-field-recording

http://quietamerican.org/

https://www.youtube.com/watch?v=0R63MOFTxx8
Nic Collins shows how to turn speakers into microphones, microphones into speakers. From the DVD in "Handmade Electronic Music -- The Art of Hardware Hacking" (Routledge 2009).

http://www.soundsofeurope.eu/about/