If you're familiar with NaNoWriMo (National Novel Writers Month) but not really into writing fiction, PragProWriMo might be right up your alley. Like NaNoWriMo, PragProWriMo is a month-long book writing event taking place each November (PragProWriMo 2011 marks the third year of this event.) However, instead of writing a novel, PragProWriMo participants are invited to write a book on a computing/tech topic.
If you haven't already guessed, PragProWriMo was created by The Pragmatic Bookshelf. During the month of November, writers can get writing advice, see progress reports of other writers, and just ask questions about PragProWriMo on the PragProg forums.
Don't forget to follow @PragProWriMo on Twitter for the latest updates!