Play the hidden flappy Android game
There's a hidden Easter Egg in Android 5.0 --- the flappy Android game. To play it, go to Settings-->About phone/tablet-->Android version. Then tap the Android version a number of times until the screen changes to a Lollipop screen. Tap the screen multiple times, then press and hold the Lollipop wording and after a while, the game appears. Tap the screen and you launch a small Android robot. You'll need to manouver it between the passing lollipops. It's a lot harder than you might think.
Pin an app for safe device sharing
Worried that if you let someone use your Android device, they may find their way into private information, or else harm the device in some way? There's a new feature that lets you share safely -- pin an app so that someone can use only that app and nothing else without knowing your password. Go to Settings-->Security-->Screen pinning. Turn Screen pinning on, then open the app you want "pinned," press the Overview button, and touch the pin icon. That's the only app that can be used without knowing your password. To unpin the app, long-press the Overview and back buttons at the same time.
Use your phone as a flashlight
Want to use your device as a flashlight? No need to get a separate app for it -- it's built right into Lollipop. Swipe down from the top of the screen to open Quick Settings, then tap the Flashlight icon. (Note that this icon won't appear on all devices.)
Use improved Face Lock
News flash: The Face Lock recognition feature on Lollipop actually works -- you can unlock your device by having it look at you. To use it, go to Settings-->Security-->Smart Lock-->Trusted Face. (Note that in order to Trusted Face to appear, you'll have to have already enabled the Screen Lock setting.) Go through the prompts for having it recognize your face. From then on in, it should work fine.
Use priority notification mode
Tired of constant notifications disturbing you, but still want to be alerted when there's a high-priority notification? You can use priority notification mode. Press the up volume or down volume key, and on the screen that appears, tap Priority. Then tap Indefinitely if you want the mode turned on until you manually turn it back off, or else tap the button below it to set the amount of time you want priority notification mode to be turned on.