Henry Blodget Reads the iPhone Manual businessinsider.com

If you’re like me, you had no idea you could easily turn your phone’s screen off. But you can! All you have to do is quickly click the button on the top of your phone that (if held down for a couple of seconds) turns your phone on and off. If you click it quickly, your screen will turn off! Then just click it quickly again to turn the screen back on. Importantly, this does NOT turn your whole phone off. Just the screen. I was astounded when I discovered this trick.

In-fucking-credible.