Check out the mp3 available from The Exploratorium "Frogs" special exhibit. I personally like to leave the 15-minute Arecibo sample running as a nice relaxing background while I program or just generally fiddle around. (Once I get my brand new Mk2 installed in the car, I predict that this mp3 all by its little own self will keep me calm in uncountable traffic-related events...)

Sounds of the Rainforest
15'

Henno
mk2 6 nr 6