jsdoit+iframe+embed

Another possible platform for delivery is jsdoit.

For instance, the racing widget is embedded at: http://jsdo.it/widged/6jZd or in full screen at: http://jsdo.it/widged/6jZd/fullscreen and the running version http://jsrun.it/widged/6jZd

Embedded into wikispaces code  code media type="custom" key="6673677"

It is also possible to embed it as a forkable activity, playable only on demand. code format="html4strict" 

code

media type="custom" key="9277562"

or the forkable code

media type="custom" key="6694483"