This is a soothing little marble mill that sends balls down a spiral ramp and cycles them back with a mill wheel. All it needs is some solar energy. Designed to work even in non-sunlit lighting conditions, Solarbotic's ingenious circuit pulses the motor to allow it to function even in sub-optimal light (though at a slower pace).
You can always just turn the hand crank if you want some immediate action.
The kit contains all the parts to build your own Marble Machine, except for tools: you will need a soldering iron, Philips #1 screwdriver and a tiny bit of glue. The wooden parts come in handy panels with additional instructions.