For those nights where you want to stay up without feeling like a zombie, or for those evenings where you don’t want sore eyes, there’s f.lux.

F.lux is a clever app with a simple idea, available for PC, Mac and jailbroken iPhones. It does nothing more than run in the background and adjust the color balance of your screen to make it easier on the eyes. Simply tell f.lux your rough location (so it can find when the sun set) and the lighting of your environment, and you’re good to go.

Download the app at justgetflux.com