Novel.

Day One:
"The great New Yorker editor and writer, E.B. White, said when accepting the National Medal for Literature, “A writer’s courage can easily fail him . . . I admire anybody who has the guts to write anything at all.”
On this your first day of writing your novel, make a promise to yourself that you are going to do it. This is critical. Without that commitment, you may as well save your pencils and paper. It isn’t going to happen. Remember, write as often as you can. That’s what writers do — they write."

http://www.peacecorpswriters.org/pages/depts/resources/resour_writers/100daysbook/day001.html
(reference: How to write a novel in 100 days or less)