Performances of Morton Feldman's shudderingly beautiful Rothko Chapel are all too rare in these parts. I attended renditions by Continuum and Florilegium in 1994 and by the Vox Vocal Ensemble in 2002; if there were others in New York in the past twenty years, I missed out. Suddenly, though, we're having a Rothko moment. On Thursday, AXIOM and the Clarion Choir will perform the work as part of the Tully Scope festival, which also includes a Cage/Feldman ICE show tomorrow. If you're tired of forking over piles of money for elitist pop culture, tickets are $25-50, after which other events in the series cost $20. Out on the West Coast, MTT and the San Francisco Symphony present Rothko four times this week, with Mozart's Requiem following. (Thus spake Morty: "For years I said if I could only find a comfortable chair I would rival Mozart.") And, over the weekend, Da Camera and the Houston Chamber Choir will give three performances in the actual Rothko Chapel, with the great Kim Kashkashian playing the viola part.... Ethan Iverson participates in a concert of works by Vivian Fine, Louise Talma, and Miriam Gideon, at Carnegie on Feb. 23.... Joan La Barbara and Ne(x)tworks explore Cage's Song Books at Greenwich House on Feb. 25.... Grisey's Le Noir de l'étoile, derived from the sounds of pulsars, descends on EMPAC, in Troy NY, on Feb. 26, and comes to Tully Scope on March 4. Les Percussions de Strasbourg are the messengers.... The soulful young pianist Inon Barnatan will present a typically inventive program in the People's Symphony series on Feb. 26. If you're tired of forking over, etc., tickets are $13.... "Mörder!" Opera Boston is reviving Hindemith's Cardillac, with Sanford Sylvan in the lead role. Matthew Guerrieri explains.