Humpday is a 2009 American comedy film starring Mark Duplass, Joshua Leonard, and Alycia Delmore; and directed, produced, and written by Lynn Shelton. It premiered at the 2009 Sundance film festival. International distribution rights have been purchased by Magnolia Pictures for a mid-six figure sum. The film opened in New York City on a limited released on July 10, 2009. Much of the dialogue for the film was improvised.