Machinarium is a charming game with an arresting and engaging art style; it debuted on the Mac and PC platforms a couple years ago. It's very similar to the point-and-click adventure games that saw much popularity in the late 80s to early 90s. You must guide a robot character through a rusted, run-down cityscape populated entirely with robotic characters and cybernetic animal life, solving puzzles along the way in order to advance the story.
The art style and music, both of which are among the best I've seen in any game from any genre, combine with an eccentric storytelling method (told entirely without words) to deliver a unique and unforgettable experience.
Machinarium was incredibly fun (and challenging) when I played it
