Chicken! That's the real game being played in "Humpday," the improvised comedy-drama by Lynn Shelton about two old college friends, highly competitive and decidedly straight, who end up daring each other to have sex together on camera. Playing Ben is Mark Duplass, best known as one of the writing and directing Duplass brothers, wheels of the super-low-budget, independent film movement known as mumblecore.

I use the term comedy advisedly, since the mood of this cautiously surreal, absurdist movie is predominantly glum. Much of the time its 28-year-old protagonist, Brian Weathersby (Paul Dano), who works as a sales clerk for an upscale Manhattan mattress company, wears a slightly stricken expression on his otherwise poker face. Mr. Dano's low-key performance types Brian as a close spiritual relative of the polite young men who drift through mumblecore films.

My new film, "Mutual Appreciation," premiered at South by Southwest, and there was some talk there of a "movement" just because there were a bunch of performance-based films by young quasi-idealists. My sound mixer, Eric Masunaga, named the movement "mumblecore," which is pretty catchy.