Okami is a video game in which you play as Amaterasu, a god from Japanese mythology. Amaterasu's mission is to restore Nippon's ecology by defeating demons, as well as to restore the faith of the Japanese (Nipponese?) people. In this aim, she is assisted by Issun, a tiny painter with a big ego, who provides comic relief from the game's rather philosophical concerns. While I don't know much about Japanese mythology, apparently all of the characters and many of the plot-elements are taken from this source.
Okami features a stunning and unique art style based on Japanese charcoal drawing. The main game-play innovation is the use of the Celestial Brush, a tool which allows you to "paint" features into the game (slash through obstacles, restore broken bridges, grow trees and flowers, and many more) which you can then interact with.
Okami's story is well-written, full of surprises, and at times genuinely moving. I actually cried (a little, anyway) at the ending, which I can not say about any other video game.
The question has been asked, "Are video games Art?" I think the simple answer to that question is "yes, they can't help but be," but the more important question is, "Can video games be GOOD Art?" I think Okami, along with a very small handful of other games, answers that question in the affirmative. At a time when films and music are often as artistically debased as most video games are, Okami has a powerful and positive story to tell, and tells it beautifully.