jQuery.filer is a simple HTML5 File Uploader, a plugin tool for jQuery which change completely File Input and make it with multiple file selection, drag&drop support, different validations, thumbnails, icons, instant upload, print-screen upload and many other features and options.
Blockrain.js is a tetris game in HTML5 for jQuery with autoplay. It's responsive and you can customize colors.
A tutorial about how to create a gorgeous, interactive animated pie chart by using HTML5 canvas element, CSS3 and jQuery.
ClassyCountdown is a jQuery plugin that allows you to easily create clean circular countdowns. It is fully customizable and includes 12 themes, which can be modified and it uses HTML5 canvas for rendering the circles.