My girlfriend once introduced me to Incredible Machine, the old-time educational and rational game which is played under Windows 98. I'm looking for the PC version and could not find the same version anywhere, until i came up with Return of Incredible Machine Even More Contraption. It's like a reborn to the game since it has won a lot of awards from PC Magazine, Computer Gaming World, Family PC, PC World, Newsweek, etc. You will love it when you play it, since it's challenging and fun to play this game.
For children, it can be used to increase their rational way of thinking and problem solving. For adults, the same reason can be used also plus another way of removing stress.
By the way, here's the screenshot from eBay: