I came upon a little game a few weekends ago and promptly stared at my computer screen for hours. The graphics were gorgeous and the game play was challenging (but not frustrating) and at the same time I was kind of creeped out by the little bug like creature I was controlling.
FlOw is the work of Jenova Chen and Nicholas Clark of the University of Southern California. Created for their masters in fine arts thesis (yup! a webgame for a masters thesis--the world continues to embrace gaming--w00t), flOw is both a visually journey in the artistic world of Chen and Clark and a great way to teach your kids about protozoan evolution. Just make sure you don't get to close to the screen--it's bad for your eyes.