Time Engineers is a really cool looking game that teaches kids fundamentals in engineering. It's aimed at middle and high school ages even though it looks entertaining (and maybe even educational) for adult engineers. The basis of the game is to unlock the time travel machine and go back to help cultures in the past with their engineering problems.  For instance you could help the Egyptians build the pyramids or design a draw bridge in Medieval France.

The thing that really tickled my fancy is the first two exercises involve principles that I've included in my PLC tutorial.   The first hurdle involves the time traveler having to use decimal to binary conversion to open up the door to the machine.  After that, a series of switches must be set using Boolean functions like AND, OR and NOT to power up the time machine.

I love educational software like this.