I figured a good learning exercise for checking out <canvas> would be to implement a small example of Conway's Game of Life using the canvas for drawing. Here's the result.
This implementation has a small twist, where as a particular cell stays alive through generations (i.e., as it ages), the shade of the cell gets darker until it turns black.
Start out by clicking grid cells to create an initial pattern, or use of the sample patterns below. Once the initial pattern is set, click 'Go' to start the game.
Some initial patterns to try: