It is said that using black and white (grayscale, in fact) screens help you focus and makes learning stuff easy. Today I suddenly had the urge to make my desktop go grayscale. Some googling led me to a piece of software called Grayscale Desktop (this is a Windows app). There’s no need to install, just double click on the Grayscale_fullscreen.exe, and there you go! To close the app you have to manually delete the process from the Task Manager.
P.S. The app eats CPU power a lot. At least that’s the case with my netbook. It’s good as long as what you’re doing is reading some book or browsing the web etc.