Dogtooth is a freaky, fascinating, elegantly off-kilter little film. Three young-adult siblings are kept confined and isolated in their sunny, serene family compound. Nothing means what it means in the closed system their trollish father has constructed for them behind the fence: They invent strange games, endure sadistic punishments, compete for stickers, and sometimes lick each other. Eventually, things get violent. If nothing else, Dogtooth (nominated for a 2011 Oscar for best foreign language film) should serve as a cautionary tale about why not to let uncanny shut-in feral children play with your cat. Never a good idea. (Grand Illusion, 1403 NE 50th St, 523-3935, $8; 5, 7, 9 pm)