This tutorial by Bill Mill takes you through all the steps needed to make a simple Breakout clone using canvas, starting at the very basics with simply drawing a circle on a canvas before moving to collision detection, keyboard input and everything else needed.

The game itself is not very fancy, it just has the most basic features found in games like these (ie. a paddle, a ball and bricks to destroy), but I suppose that is expected since we're dealing with a tutorial and not a full game. If you're looking for something more advanced in terms of gameplay, I suggest you check out DHTML Arkanoid.