(AU VOLEUR! ARRÊTEZ-LE!) The art thriller of the 20th century began March 18, 1990, when two unarmed men pretending to be police officers walked off with $300 million in art from the Isabella Stewart Gardner Museum in Boston, including the priceless Vermeer The Concert. Then things really got colorful. Documentarian Rebecca Dreyfus captures it all: the devotion, the intrigue, the Irish mob connections, the 75-year-old art detective who wears a bowler, the $5 million reward, and most of all, the fact that everything is still missing after 16 long years. (Northwest Film Forum, 1515 12th Ave, 329-2629. 7 and 9 pm, $5–$8.)