A quick experiment building a game with the Web Audio API turned into a viral hit.
The Web Audio API, which was only supported in Google Chrome when I built this, is a firmly cemented brick in the future of the web.
This was my first try using it, in a game I built on a lazy Saturday afternoon.
In November 2013 it suddenly took off, receiving millions of hits in just a few days. In its first week of popularity over three million cows were found and it continues to entertain people the world over.