I stumbled upon this neat little "game" today and promptly lost about an hour (maybe two) of my day...
http://www.earslap.com/projectslab/otomata
(and yes, it's way better with headphones)
and something for us sciency types...
http://www.earslap.com/doodle/combination-tones-and-the-non-linearities-of-the-human-ear








