game-modules
A list of game-related modules and examples for writing HTML5 games with browserify.
Browserify is a general-purpose build tool for client-side development which essentially lets you use node.js/npm modules in the browser, but it also fits pretty nicely into HTML5 game development. The best example project would be voxel.js, which is using browserify and npm extensively to bring Minecraft-like voxel games to the browser.
The one issue is getting started. That means project setup, getting familiar with browserify and the Node ecosystem, and most importantly: discovering modules (npm has >35,000 packages right now).
In the wiki you can find a list of modules you can use in your own games, and a list of projects built using browserify.
Even if you're using your own toolchain, some of these modules should serve well as nice and compact reference implementations for your own projects.
If you're interested in browserify or node.js development in general, you should check out Max Ogden's Art of Node.