Just watch the falling circles. Listen to the ever descending tone. Enjoy. Make sure to turn up your volume! Doesn't time seem to slow down if you focus on the smaller/slower circles?
The tone is called a Shepard tone. It sounds like it is going down, down, down... But actually it isn't. :D I hope you enjoy! Read about it on Wikipedia. http://en.wikipedia.org/wiki/Shepard_tone All by me! If you want you can use the loop-able version of the "falling" sound I made. (But give credit please!)