I'm taking a break from novel-writing* (although I shall still write the odd short story) and am currently writing a non-fiction book. As it's largely about my own experience, I don't have to think up a plot or an ending (or even a middle) because it's all there in my head. And today, I got my agent's approval (I'd sent her the opening), so I can go ahead with it. Quite exciting!
*I shall return to it when the idea in my head has gelled. It's taking its time at the moment.