This Daydream app for Android 4.2+ users is awesome. It has nice animations and a great settings menu. You can set the background, colors, fontsize and more. But the best thing is, the daydream has a energysafe mode. After the timeout ends (adjustable) the daydream switches to an other view with the clock only. You need to click on the screen to get the main view back.

A few functions listed:
- AM/PM function (automatic)
- Choose background
- Choose color
- Timeout for energysafemode
- Battery level
- Fullscreen
- Black/white filter
and much more!

How to setup (Step-by-step):
- Go to android settings > display > daydream.
- Choose the Modern Holo Daydream
- Go to the Daydream settings of Modern Holo Daydream to customize it
- Press "start now" to see a preview