Technically, the masterminds behind Ballroom Marfa, a haven for contemporary art in West Texas, could have uncorked the celebratory grand-opening bubbly last fall, when they opened their spacious cultural center. But so much for technicalities. The official christening for this dance hall turned gallery begins with the April 23 opening of “ OPTIMO: Manifestations of Optimism in Contemporary Art,” a multifaceted hodgepodge of creativity from nine artists. The exhibit is a party in itself, and like all good shindigs, visitors can expect lots of balloons (as in nearly a roomful, thanks to Martin Creed and his Work No. 200 “half the air in given space”), bouquets of flowers (via Beatriz Milhazes’s abstract painting Ovo de Páscoa), a gracious welcoming committee (giant eyeball balloons by Takashi Murakami, which once found a home in Rockefeller Center, will float above the Ballroom Marfa rooftop), and much more. The festivities close June 27.