Desktop Tower Defense

If you're not already hooked and you have some time to kill over the holidays, head over to The Casual Collective and try some Desktop Tower Defense. This free Flash game involves building and upgrading a variety of defensive, immobile tiles in order to prevent "creeps" from crossing the screen. It's incredibly engaging for such a simple concept, and it has to be one of the most imaginative Flash games to arrive this year. In multiplayer mode you compete against other players for the best completion time. Be warned that once you start, it's not easy to stop, particularly until you've conquered the practice round. (Thanks Eric.) Merry Christmas everyone!