This semester I took a class called Multimedia Programming, where I did a lot of work animating in HTML 5 Canvas. This was my first semester working with canvas, so my skills are at a very beginner level and all of my animations were really simple (e.g. moving an image across the screen).
However, I'm always amazed to see how beautiful and complex animations can be made in canvas. The link below leads to a really cool cycle made by Mark Ferrari and Joseph Huckaby. While you're viewing it you have the option to click through different animated landscapes, change the cycle speed, and view the color palate.
I was really impressed by this when I first saw it, and honestly it's still my favorite thing I've ever seen done in canvas. I'd really like to be able to produce work like this eventually!