The past year plus, whenever I've had free time, I've used to it to familiarize myself with WebGL, a new technology that allows some pretty awesome graphics to work in your browser without any plugins (utilizing HTML5's <canvas>). Part of that time has been spent developing a game (which can be very hard work), and I even used the technology to make my girlfriend's anniversary gift.
Most software has moved to the web in the past 5 or so years, and games are sort of an exception. Of course there are web games, and some very popular ones at that (Farmville, Words with Friends, Sims Online, etc), but no truly awesome 3d games. With WebGL, hopefully that can happen.
There are even projects in the works to get this all working with gamepads. As I was developing my game, I made use of APE Project to handle multiplayer connection, so if you're interested in developing a multiplayer game, consider that.
WebGL is something I hope to continue working with, I've always been fascinated by video games, and I have a few ideas up my sleeve - so watch out!