MacHeist NanoBundle pointer
MacHeist runs occasional deals on Mac software and right now there's a pretty good one: Get six Mac apps, absolutely free.
I'm not familiar with most of the apps but the one of them that I am makes the whole bundle worth getting. WriteRoom.
WriteRoom gives you a completely distraction-free screen to write in. It works like TextEdit, but when you hit Escape it toggles between a normal Mac window, and a full-screen green-screen style console.
It's a unique way to get some writing done. Definitely worth the price.