A Canadian team has been asked to "re-invent" the wheel. It is part of an effort to make more efficient micro-rovers for future  space-exploration.

McGill University  has joined a work-group called Neptec, in the effort to develop new ways of exploring other worlds with micro-rovers. Neptec has brought together the industry’s leading technology experts to develop the new Lunar Exploration Light Rover. This highly experienced team has been working together to develop rover technology for the Canadian Space Agency for 4 years.

Small in size but not in capabilities, microrovers may one day play a larger role in exploring other worlds.  A rover is considered a micro-rover when it is smaller than 12kg

Planetary Society has compiled a catalog of known microrovers that have already been built or designed, ranging in use from military applications to planetary exploration Their list is available in the link below. Only one of the microrovers has actually visited another world - Sojourner (part of the 1997 Mars Pathfinder mission) - and is small enough to be considered a microrover.

Microrovers can help clear bombs, reconnoiter dangerous territory, inspect pipes, or examine rocks on an alien planet. The catalog can serve as a single public location to showcase micro-rover technology in all its variety, a starting point to see what work has been done before embarking on new design projects.

Source: McGill University
SEE LIST of existing micro-rovers