Bedtime mode is a key feature for many BlackBerry users, used for many purposes, a clock, making sure your alarm is on/of, looks nice & comes in handy. Check out the rest of the images of Bedtime Mode on BlackBerry10
To activate the bedtime mode, you need to swipe the screen from to bezel to bottom of the screen.
If you want to turn off the Bedtime Mode, you just need to swipe your finger from lower bezel to top of the screen.
There it is, a simple look at Bedtime Mode on BlackBerry 10.