Everything is connected. At least in some screenplays, and it takes an artist to make the contrivance look like serendipity. The title slacker (Jason Segel) in the Duplass Brothers' meditation on fate and fatuity is obsessed with M. Night Shyamalan's Signs, and the filmmakers' gentle irony about his bad taste exemplifies their empathy and tonal skill. Jeff is 30 and lives with his mother (Susan Sarandon), who gets him out of the basement with an order to buy some glue to repair a slat in a cabinet door. But Jeff has another blurry mission in mind, a destiny that involves a wrong number, the name Kevin, and several hits on a bong. And so the story follows his determined search for resolution, despite the mocking skepticism of his pompous, feckless brother Pat (Ed Helms). Maybe it's Segel's sad naïveté, or the filmmakers' inventiveness and metaphorical dexterity, but even when the contrivance kicks in, it seems like Jeff might have the right idea.