One of the HTML5 features that attract me a lot is <canvas> tag. Imagine a blank canvas in real life. You can paint it with any colors, any shapes, whatever you want. So using this tag, we can draw anything, make the shapes moving, even make any interaction between them.
It’s only 70KB, easy to understand, great documentation, plenty of samples, and great performance. Right now, I’m still exploring this KineticJS, but soon I’ll implement it in some works and project 🙂