Growing up, I used to live out in the middle of nowhere. At night, during the full moon, a kid could run all over the place without needing a flashlight thanks to our nearest celestial neighbor reflecting the sun's light (about 10%, in fact). The Civil Twilight Design Collective has come up with a cool idea for a street light that gives back to city dwellers by making use of those moonbeams.

Lunar-Resonant Street Lights sense the amount of light the moon is reflecting and dim according to its phases. The designers claim the lights' highly efficient white-LED clusters are 90 to 95% more energy efficient than regular street lights. It's a bright idea but only a design concept right now.
— Stephen Schleicher

Civil Twilight Design Collective, via Tree Hugger