A fractal animation by Louis HoebregtsA vector fractal animation made with RaphaelJS. The JS looks a bit daunting at first, but it is worthwhile to look into how this is done. The techniques behind fractal creation in programming are generally simple concepts like recursion that produce fascinating results.
Swinging Lightbulbs by Brandon LawrencePure CSS swinging lightbulbs. My mind can completely grasp fractal generation, but CSS transformations are for some reason beyond me. It's easy to see its power though so definitely a good skill to have under your designer belt.
Memory Game by Nate WileyAwesome memory card game built with easy to follow JS. I used to play this game at my grandma's house with real cards and it's a lot easier when you can just cheat by peaking under the glass coffee table to see the card faces. Still have a perfect memory though. ;)