xsamples.caist.com
a little 3d navigation and a lot of free mp3-songs
actually it is not a flash-site, but it uses an interesting 3D navigation and an actionscript-scrubbing-technic so the movement is always soft. So the action you see is more coding than you would think in the firstplace. there will be a tutorial which explains the technic. the content of the site is about experimental music.