Android’s Daydream feature is an “interactive screensaver mode” that can activate automatically when your device is docked or charging, keeping your screen on and displaying information. Daydream mode can give your device an always-on information display.

Developers can create their own Daydream apps and Android includes a variety of built-in options. We’ll cover what you need to know about Daydream mode and how you can use it to make your Android device display useful information.

via How-To Geek http://www.howtogeek.com/170990/5-cool-uses-for-androids-daydream-mode/