One of my fellow technology evangelists has written a little library of javascript for use in designing simple games with touch, music and sound effects.  The nice thing is that it is a small set of code and Dave Isbitski has carefully documented the small game engine on his blog at: http://blogs.msdn.com/davedev.

Download the Win8GameKit at https://win8gamekit.codeplex.com/ , the demo game shows you how to build a simple HUD (Heads up display) Scoring, Simple touch on a moving object and so forth.