A Noise Machine
If you don't take anything else away from this list, take heed of this night-changing app. The Simply Rain App is an elevated form of white noise, projecting the sound of little rain droplets streaming down a window on a repetitive loop. You'll be lulled into rest so quickly, you won't know what hit you. My entire family uses it and can't live without it. Approved.
Simply Rain App, $1
[Photo via @happilygrey]