Flip the Switch

This is the best way to turn off a light switch
The Hook

Place a hook with a screw in the ceiling.
The Pulley

Hook up the pulley on the screw.
The Dustpan

Set up a dustpan that can be lifted by the pulley.
The Ramp

Set up a cardboard inclined plane that lays on top of books.
The Lever

Get a dustpan that has a handle that can tilt and set it up.
The Light Switch

Tie a string from the dustpan handle to the light switch.
The Ball

Place a baseball in the dustpan.
The Beginning
Pull the pulley so the dustpan lifts and the ball falls out onto the cardboard ramp.
Hitting the Handle
The baseball will hit the handle of the dustpan and knock it over.
Flipping the Switch!

The handle will fall, pulling the string and turning off the lights.