I'm not doing NaNoWriMo.
I feel fairly certain that I could write a 50K novel in a month--but I'm also fairly certain that any novel I wrote in a month would stink like a slaughtered hog in the sun. And it would be a big time commitment for me to do so--time that I could be using to prepare my D&D game, spend time with my wife, and so forth.
So for me, the joy of creation is outweighed by the opportunities to do other things.