Another great build-it-yourself from Gakken's Otono no Kagaku series, Vol. 33 allows you to create a Pacman-like Robot Vacuum Cleaner that can move around by itself, sweeping up the dust and dirt on your desktop. It can detect edges so won't be falling off surfaces, and can also change direction and move around objects completely unaided.
Spend around a satisfying hour building and then amaze yourself and your family using your robotic creation. And the truly curious can even customize the cleaner to give it a special look or different functionality.
The Otona no Kagaku Robot Vacuum Cleaner features: