f.lux is makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day.
Smarter controls and a new Adaptive algorithm for your external displays.
• the brightness/contrast can respond to the built-in light sensor readings
• use the brightness keys to adjust external monitor's brightness
• the behavior of the algorithm is now adjustable through global brightness/contrast offsets on the settings page
If you work with multiple monitors sometimes you'll want to focus on the primary one.
And hey, that's just what Dimmy does.