NaNoWriMo? It's a push to get that writing project out of your brain and onto paper, it's super helpful for some people just to have something telling them to do the thing.
NNN? Test of self control. "I can quit any time I want" is something addicts say when they can't quit any time they want. It's also super easy; if it feels like masochism to not nut for more than a week, you're addicted.
National Novel Writing Month, often abbreviated NaNoWriMo, is an annual event encouraging people to finally write that novel they've always said they would. The goal is to write 50K words during the month. There are usually meet ups, writing workshops, and other gatherings so participants can encourage each other, share ideas, and generally have fun being part of a thing.
Edit to add: The "nation" is the USA I'm assuming. I'm in the USA and have only heard of it being a US thing. Presumably if you live somewhere else and want to write a book in November, the various online communities would be glad to have you though.
Some ridiculous percentage of all currently publishing novelists in the US have an MFA in literature or creative writing or something similar. If this makes you feel a little suspicious about how the publishing industry actually works, it should. It's very much a closed ecosystem that's all about recycling the tried and true and that is highly risk averse in terms of straying from the norm. This is why it's almost impossible for "regular" people to get a novel published unless they self-publish.