This was a fun exercise from the Colt Steele developer bootcamp using Paper.js to make circles and Howler.js to create a sound. If you type on a letter key, it creates a colored circle that that fades off the screen while it plays a tone.
This was done using basic Javascript with the Paper and Howler libraries.
http://www.brianhafnertech.com/Apps/patatap/circles.html
Github: https://github.com/jbhafner/patatap-circle