This simple and elegant Flash game looks like a work of art: minimal design paired with maximum gameplay. While not an original concept, Gridlock features classic sliding-block puzzle gameplay that will surely exercise your brain. Each level holds a blue block that you must slide through the opening. Slide any of the blocks necessary to achieve your goal. Progress is saved automatically.
Corwin Derkatch of Canada has been hosting this game for a couple of years now, and I continually see references to it popping up. A very well-executed game in the genre, and a very beautiful game to behold.