flOw
flOw is a neat little game for Playstation and PC in which you play an organically evolving organism, floating around in the deep-sea, out to devour little plankton-like pieces while a Brian-Eno like ambient backround music sets the tone.

The critics say there's not much of a point to the game, that it's more like a lava-lamp than a goal-oriented videogame, but that may just be the beauty of it.

And of course, the fact that you can play it online for free here.