"The Idiots" was directed by Lars von Trier in the conspicuously freewheeling style--improvisatory acting, hand-held camera work, etc.-- favored by the Dogma filmmakers, a Scandinavian group inspired by von Trier's work in "Breaking the Waves" and "The Kingdom," his rollicking TV series. The title characters of "The Idiots" belong to a sort of latter-day hippie commune; they live in a country house borrowed from someone's rich uncle and spend their days "spassing," which means pretending to be mental retardates who can't be expected to lead responsible lives. They're fond of criticizing others for being "middle class," but it's hard to imagine a household more self-indulgently bourgeois than they themselves, whether they're having a perfunctory gangbang, smearing caviar on their faces to show how wasteful they can be, or daring each other to "spass" in front of their families or bosses. All the wobbly camera work in the world couldn't make this aimless stuff socially provocative or politically challenging. Von Trier needs to rediscover the narrative boldness of his great "Zentropa" if he's going to keep his career moving in the stimulating directions he once appeared to have charted out for himself.