There are a few games that I really enjoy. There are the plot-heavy RPG's that draw me in for hours and the casual games that draw me in for hours. Sometimes, it's nice to find a game where you can start it up and just play around with it, then look up to find out that you just lost half a day.
Crayon Physics Deluxe is one of those games. A very simple game, relatively speaking. You draw boxes, chains, and hinges on the screen and get a ball to roll into the star. The wonderful part of the game is not the complicated puzzles; most of them can be solved by brute force. Instead, the draw of the game is how you can solve a puzzle. The program doesn't have "one true way" to figure out a stage. I lost hours trying see how complicated of a Rube Goldberg device I could create. I realized this at some point when I managed to build a catapult to launch the ball into a series of tubes just to get it along a straight line.
And that is the joy of the game. Not finishing a stage, you could probably do that in a few hours, but finding cool ways of finishing a stage, something that someone else might not have thought of.
Obviously, I would rather there be a Linux version of the game, mainly because that is my operating system of choice, but this will definitely hit the magic point of good entertainment for me (money paid divided by hours of entertainment is less than 1). I'm already 6 hours into that and I just installed it yesterday.