A "distraction free" word processor for Mac OSX that consists of nothing more than a background (in a color of your choice) and a single column of fixed-width text. The application launches full-screen so you don't see any menus or your taskbar unless you command-tab. I think it is supposed to emulate a typewriter setting. The program used to be free, but now you can pay $25 for the privilege of using it after a 30-day free trial. There is a windows version of the same program called Darkroom.
You can download the program here