In addition to being a fascinating toy, the ZéCar flywheel powered car can be utilized in physics curricula to study conservation of energy.  It is available from a variety of sources, including teachersource.com for under $14.  In this lesson students study energy conservation, including gravitational potential energy, translational kinetic energy, rotational kinetic energy, and work done against non-conservative frictional forces, with emphasis on comparing ZéCar with the PocketLab Teacher Geek® cart.  Data from PocketLab Voyager’s range finder can used to determine translational velocity  for ZéCar.