If you're interested, I wrote a short overview of some of the more "popular" art games a bit ago:
http://www.bagofgames.com/2012/06/i-dont-know-much-about-art/
Speaking of Tale of Tales, Bientot l'ete looks like it will be interesting. Got a peek at the alpha, and it looks as if it's another game centered around players trying to communicate with a somewhat limited vocabulary, much like their earlier multiplayer game The Endless Forest.
I would draw a distinction between art games and games that are artful. Yeah, splitting the semantic hair here, but to take an example, Limbo was a beautifully executed, lovely to look at, broody platformer. But I wouldn't call it an art game in the sense that Braid is, mostly because it's not really trying to say anything other than "experience this strange world". Not that there's anything wrong with that, as Seinfeld would say, and in fact Limbo is a terrific game while Braid's narrative is sometimes a bit too self-indulgent. But the aims of self described art games tend to be something other than pure gameplay.