With SpritePad you can create CSS sprites simply by drag & drop your images. Available on Firefox and Chrome at the moment.
8 crazy animations with WebGL and HTML5 canvas.
Responsinator, a simple & effective way to test your site design on a range of popular screen sizes.
StyleDocco generates documentation and style guide documents from your stylesheets.
Learn Game Theory and more via Stanford University's free online courses.
Kraken.io, optimizes images and code online.
Learn HTML5, a collection of useful tutorials and guides.
Build your own infographics in a few clicks with Visual.ly.
Time.is - exact time, any time zone.
Post-mortem on developing a simple HTML5 space shooter game.
10 cool HTML5 games and how to create your own.