As part of the Moshpits project project, I created an interactive simulation in javascript. Initially just to learn about the basics of HTML5 canvas, it become very useful for exploring parameter space and also become very popular on 'teh internetz' when interest in the project picked up.
I even created an embeddable version where the controls are hidden so as to maximize space utility. It was included in articles on:
The main page has more information on what exactly is going on in the simulation. Also, the source code is available on my github here.