So I'm confused. What exactly is the point of this? To stop "light pollution", global warming, what? *Teleports to time in the future*

President of the United States: My Fellow Americans, we have finally reached the point where we are almost out of usable energy but we do have a small amount remaining. You see, back when primitive thinking was still heavily exercised (about 25 years ago), one day a year, one hour in that day, a few people would turn out their lights and call it "Earth Day". Well it turns out that we've accumulated about 50 hours worth of light. Except, that was 50 hours of people that conserved during that one hour which equates to less than a day left of energy for the general public. We are working on another source of energy so do not panic.

... Yeah, that's really going to work.

P.S. Look at google.com