I'm not much of a game player, but this one looked so beautiful, I had to try it. Machinarium is an adventure game, for Windows, OS X or Linux (I ran it on Linux).
You play the "story" of a little robot who is thrown out of a robot city prior to the game. I won't say anymore about what happens as part of the whole experience is discovering that story.
There is a little hint game, that reminds me of space-invaders that you can play if you get really stuck - my son ran those parts for me while I worked on some of the trickier puzzles.
The soundtrack is simply amazing and other-worldly. They give you the tracks to download when you buy the game - they're worth listening to all on their own.
The demo is free, give it a try, but I warn you, you'll want to buy the whole thing - it's worth it.