Autonomous Snow-clearing Robot
A robot, for sidewalk and bicycle paths, that can autonomously clear them for snow (i.e. throw snow to the side, or an even cooler way of removing the snow like vaporising it).
It should be very careful not to harm any people or animals.
A major challenge is probably to locate e.g. the bicycle path if it is covered in 20cm's of snow; GPS is probably to imprecise, and markings on the asphalt cannot be seen (except where the clearing has been successful). Maybe sound buoys can be used to guide the robot, using inaudible sound ranges?
+ 
= AWESOMENESS!