When you are a writer and you just dont have enough will power to fight back procastination. then Writeroom just might be the tool you are looking for.
Distraction free writing. For developers, distractiong free code writing. Although this Writeroom app isn't that suitable for code writing. A full screen terminal with Vi is a handy substitue.
Nowadays, I too try to to turn off all apps not needed to do the task at hand. Unitasking sometimes helps a lot in getting things done (GTD).