Instructables: The Game!
I think it's a great idea, but I wouldn't even know where to get started on the technical aspect, nor the legalities involved.
The game is basically a walk through an instructables-inspired home-built city of interesting devices and systems all loosely (or even exactly!) based on actual instructables.
During the games as you explore you stumble on different tasks that you have to complete. You find parts to complete tasks scattered about the city, or win them for completing smaller tasks.