Why would someone put themselves through a month of nonstop writing without being paid? For the challenge of it! Having to write a certain amount of words everyday or week can also get you into a routine of writing on a consistent basis, which is a huge challenge for many writers.
To participate in the NaNoWriMo Young Writers Program, you register online and track your writing progress through the site. For the 18+ challenge, just click here. I'll be attempting this feat so feel free to chat me up when you need motivation or if you need to commiserate with another WriMoer.