National Novel Writing Month (NaNoWriMo) takes place every November. The idea is to crank out an entire novel in one month, abandoning quality for the sake of quality.
NaNoWriMo.org acts as a resource for the project, allowing you to track your progress and network with other writer's attempting the same project.
NaNoWriMo.org -National Novel Writing Month
The official site for the National Novel Writing Month.