This year will be year 5 for me. I love doing NaNo. I have no idea what I'm going to write going in (usually) and just WRITE. Last year I had an opening scene in my head and it wound up taking on a life of its own and was immensely fun to write. I usually go to the forums, pick up a ton of challenges, and see how many insane ideas I can fit into it. It can be a blast if you let it be and don't get bogged down in the fact that you really don't have time to worry about every word that goes on the page. Good luck, with your novel!