Google introduced Daydream in Android 4.2 but what is it and how do you turn it on? Interestingly Android 4.2 drops a number of hints about docks and docking modes. Daydream is what PC users would call a screensaver mode, it displays a set screen when the tablet is docked or just left charging.
To turn on and adjust Daydream settings select Settings > Display > Daydream. The default offerings include Google Currents, Colors, Clock and a couple of photo options. It’s obviously designed for use in docking situations and hopefully make more sense as more Daydream updates are added.