Android (5.0+): One of the neatest features of Motorola's Moto X is that you can see your notifications at a glance as they come in. Glimpse brings this feature to all Lollipop devices.
The app works by automatically turning your screen on when you receive notifications from certain apps. You can designate which apps will wake your display. Then, just set your phone on your table or desk and keep an eye on it. Glimpse also comes with a Pocket Mode that disables the wake feature whenever your phone is in your pocket, to conserve battery.