Hello World! in allegro.js. This example initialises graphics and displays a centred 'Hello World!' message in the middle of display. It only takes 4 lines to do all that, so check it out!
Bitmap loading and blitting. This example loads a bitmap from files and displays it stretched on screen once it has loaded. It requires whooping six lines of code to make it happen.
allegro.js stress test. You wouldn't believe how many sprites you can display on your machine at 60 fps. Note that the performance may vary across browsers.
allegro.js unit test. You should not learn from this, it is used to make sure that everything inside allegro.js works fine and consistently across all browsers.