Fully 20% of this festival’s concert programming (one of Centrum’s summer-long arts offerings) consists of contemporary music. OK, there are only five works in all on two concerts, but still. Artistic Director Helen Callus, late of the UW School of Music, is new-music-friendly (as are most violists, whose instrument got cruelly shortchanged by 18th and 19th-century composers), and has brought composer Paul Moravec for a performance of his Pulitzer Prize-winning Tempest Fantasy for violin, cello, piano, and clarinet. Surrounding it on tonight’s program is music by Smetana and Prokofiev; on tomorrow’s concert, Brahms’ Piano Quartet in G Minor and Schubert’s String Quintet.