Here is a robotic ball that entertains your kids and teaches them basic programming concepts. The SPRK+ Robotic Ball can be used to mimic the solar system, navigate a maze, and perform other tasks. It has a simple visual interface for programming.
SPRK+ comes with an inductive charging base. It has Bluetooth with 100-foot range. It can go as fast as 4.5 mph. You can get yours for under $130.