The Metropolitan Museum of Art, which is usually closed on Mondays, has opened its doors until 5:30 p.m. tonight. So start your "more museum-going" resolution early and check out Tapestry in the Baroque: Threads of Splendor, which closes on Jan. 6 and the new galleries for 19th and early-20th century European paintings and sculpture, which feature a French art noveau assembly of "The Wisteria Dining Room," by Lucien Lévy Dhurmer. There's Henry Lerolle's gigantic church interior The Organ Rehearsal.