Blackout

BlackOut is a free and small utility with mainly one purpose - to paint the screen black, and keep it that way. It is not a conventional screen saver, which means you start it manually whenever you want the screen to go black.
You might ask yourself when you would ever need an application that simply paints the screen black, but there are times when the program comes in handy.
I for example use the program when Im using the computer as a DVD player. Since Im watching the films on a TV, I want the monitor to be blank. However, the DVD player software prevents the system screen saver from being activated (otherwise it would be activated when watching films on the monitor), and this is when BlackOut comes in handy.
Once activated, BlackOut can be minimized by pressing a key on the keyboard or by clicking a mouse button (exit the program by pressing Esc). When BlackOut is not minimized, it checks every other second to see if another window has poped up in front of it, and if so it will force itself to the foreground so that it will always cover the entire screen. When BlackOut is active it will also prohibit the system screen saver from running, so if you want stop the screen saver from running and perhaps steal processing power, you can activate BlackOut instead.