I was just introduced to an excellent game called Roller Coaster Challenge that melds puzzle solving, creativity and fun. It's a logic-based, free-form, build-it-yourself kit that tasks you to get from point A to point B by using a limited number of coaster parts.
Every level in the game challenges you to build new structures while building on learned concepts. As you complete tasks, you'll be surprised by what's possible and it will make you want to go off the grid and create your own layouts.
As you can plainly see from the video below, John's "Blue Flash" invention was no doubt inspired by this game.
My wife tutors children who have a very difficult time focusing but Roller Coaster Challenge captures their attention and instantly gets them into the concentration zone.