Focus Booster is a free application designed to improve time management by forcing you to stay focused in 25 minute intervals. It's based on the principles of the Pomodoro technique which postulates that mental activity can be increased with frequent breaks.
The name Pomodoro comes from the Italian word tomato which was apparently the shape of the kitchen timer that inspired the technique. I've used focus booster and oddly enough it does make time feel fleeting especially during those moments when I'm sipping my seventh cup of coffee and wondering if I'm not really the worst writer ever.
Use focus booster and I guarantee you will write something. It won't be as long as the Magna Carta or as riveting as the recipe for Mac&Cheese but at least you can still say you're a writer.