Although symphonic music is his milieu, the most accurate description of Gustavo Dudamel is "rock star." At just 27, the dynamic young conductor has set the classical world ablaze with his passionate style and charisma. A product of "El Sistema," Venezuela's vaunted music-education program, Dudamel conducted the country's national youth orchestra in his teens; he's since rocketed to the big time with international raves, a laudatory profile on 60 Minutes, and a five-year contract to succeed Esa-Pekka Salonen as the music director of the Los Angeles Philharmonic. Tonight, "Gustavo the Great" kicks off the first of several shows this week with a varied program, including Brahms' signature Symphony No. 2.