I wanted to get some more practice making interactive structures with JavaScript and canvas, so I made another art-type piece where one can make growing circles. Although I'm too lazy to make instructions on my page, the user merely clicks on the screen and bubbles start to form. Eventually, at some random point, the bubble bursts!
The code wasn't too challenging to write, especially after my falling circles code, but it works. The code is over here at jsfiddle, and below.