Notebook: Machinarium (a very cool problem solving game)

MachinariumRAR 280M  

Known as one of the best modern problem solving games. Non-voilent. Help a robot move through a world of bully robots, solve social problems etc.  Unzip the contents into a directory on your computer and play off those files (if you play directly from the ZIP file it won't save your games).

Search Google for walk-throughs for some of the more challenging problems.