November.
The month before Christmas. A mere 30 days, with a nice food ridden holiday(and 3 day weekend) thrown in.
November is also National Novel Writing Month.
Join 100,000 participants as they try to write a 175 page, 50,000 word novel in 30 days or less. (In 2007, over 15,000 finished.) NaNoWriMo.com is a non-profit organization that sponsors the event, and everyone (that finishes) is considered a winner.
Good Luck!