Keiko Takahashi made these adorable little measuring tape robots. They move like snails, slowly inching forward. Her project is called "Meter Crawler":
A meter crawler protrudes its steel measure four or eight cm. The body of the crawler follows the steel measure and thus moves forward. When it is taken away from floor, it stops moving, and the steel measure holds into the case. When it is on a floor, it starts protrudes its steel measure and move forward.
Video at the link.
Link via CrunchGear