Two straight guys decide to have sex for an amateur porn film festival. Ninety percent of the movie you’re wondering why they want to do that, are they secretly gay, and will they get around to, well… humping. Naturally, gay audience members love this premise, said Humpday’s director, Lynn Shelton. But the test for Humpday won’t be in the Castro’s movie theaters – where it will be a sure hit -- as much as in movie theaters frequented by straight guys who may have a deeper aversion to discussing buddies crossing boundaries than any other subject.