OS X: HazeOver makes it easy to focus on the task at hand, even if you have multiple windows open on your Mac. All it does is dim background windows and your desktop, while keeping the front, active window bright on top of all of them. When you switch so does the lighting, helping you to stay focused without distractions. The video above is a perfect demo of how the app works. As long as it's running, the app you're working on will be full-brightness and the focus of the screen, while the others dim and fade out in the background. Eagle-eyed readers may remember we mentioned this app years ago when it initially launched. It's come a long way since then, with snappier, faster focus switching, adjustable brightness and dimming intensity, tweakable animation duration (so you can slowly dim windows, or make it super fast), and an interactive menubar icon so you can adjust the app's settings without actually opening the app itself. HazeOver now supports multiple monitors, trackpad gestures and keyboard.
Of course, with more features comes a price to match, and the app is available now for $5.99 in the Mac App Store. Hit the link below to see more screenshots of it in action, or to grab a beta version (which you can get by contacting the developer).