"Cy Twombly: Treatise on the Veil" This rarely exhibited painting by Cy Twombly is accompanied by several works from the artist's private collection that "document," in a sense, the piece's creation. Treatise on the Veil comes from Twombly's "gray-ground" period (1966-1971) and very much resembles a huge chalkboard with a mysterious musical composition drawn across its lower half. The work was inspired by Pierre Henry's musique concrète composition The Veil of Orpheus, and it represents the moment in the myth when Orpheus, in an attempt to rescue his dead wife Eurydice from the underworld, breaks the rules of the gods and looks back at his wife, thus losing her forever — one of the most heartbreaking scenes in literature. That musical moment in Henry's composition is rendered as the sound of fabric tearing. Twombly, in effect, attempts to represent that sound in his own invented musical script. The piece is powerful in its size (nine feet by 32 feet) and simplicity. It's truly operatic. But the additional works on display don't necessarily support or detract from the major work. Twombly's always best when he goes big. We don't need to see the rehearsals. Just give us the performance. Through February 14. The Menil Collection, 1515 Sul Ross, 713-525-9400. — TS

"Hypnopomp: Britt Ragsdale" A haunting, humming audio emanates from the sheet-draped forms that cling to the walls and floor of Lawndale's room 317. After a couple seconds in "Hypnopomp," Britt Ragsdale's third-floor installation at Lawndale Art Center, you realize that the crumpled sheets seem to obscure bodies curled in the fetal position or sprawled in sleep — or maybe death. You begin to pick out the shapes of hips and rears and shoulders from the mounded terrain of the fabric. Are they people, or are they apparitions? Do you dare peek under the fabric or place your hand on a shoulder? The sheets are cream-colored, rather than a cold white, lending a warm somnolence to the sculptures. (FYI: They were created by molding wire mesh over models, and the baroque folds of the drapery are held in place by liquid starch.) The figures on the walls, stuck there like spitballs, are most unsettling. Through incredibly simple means, Ragsdale has conjured up a hallucinatory, otherworldly environment. Through December 19. 4912 Main, 713-528-5858. — KK

"Lisa Orr: Epergnier" Lisa Orr's functional ceramics blend funky forms together with richly colored and loosely applied glazes. There is a freewheeling Rococo vibe to Orr's work; the Austin artist adds bits of molded clay ornamentation and even employs pastry bags to create icing-like swirls on her objects. For her exhibition at Optical Project, Orr is showing everything from over-the-top tiered vases and large serving bowls to skewed coffee mugs and a little, marvelously goofy butter dish. It's inspiring to see functional objects created with exuberance — it'll make you want sign up for the nearest ceramics class, or at least do some holiday shopping. Through December 24. 1125 E 11th St., 713-863-7112. — KK