What happens when a 6 year old in a basement full of materials for elementary engineering gets an attack of summer boredom? A Rube Goldberg (or as the rising 7th grader says, a "Babe Ruth", a "Ruth Goldberg!") machine and an hour of (non-screen) fun!
Not sure what's going on? The marble goes through the run and hits the "dominoes" which fall and, in turn, knocks the knife switch over, completing the circuit and turning on the light!