A LITTLE LATE-NIGHT MUSIC.

A decade ago, the Mostly Mozart Festival, Lincoln Center's venerable summertime series, was offering some of the dullest concerts in the Western Hemisphere. I remember a performance of Mozart's Flute Concerto in D, with Jean-Pierre Rampal as the soloist and Gerard Schwarz conducting the Mostly Mozart Festival Orchestra, which was positively bureaucratic in its self-satisfied mediocrity, as if it were being piped in from a department of motor vehicles in Leonid Brezhnev's Russia. I briefly considered abandoning music criticism for cat-sitting.

In the mid-nineteen-nineties, with the advent of the multidisciplinary, hipper-than-thou Lincoln Center Festival, many people assumed that the older series would fall by the wayside. Instead, Mostly Mozart has undergone a mildly shocking rejuvenation. The programming now includes periodinstrument ensembles, dance (the Mark Morris Dance Group performed its masterpiece "L'Allegro, il Penseroso ed il Moderato" last week), even world music (Kayhan Kalhor, the kamancheh virtuoso, appeared last summer). Late-night concerts have been added, and a new stage has been installed at Avery Fisher Hall. The orchestra, which draws on New York's inexhaustible supply of skilled freelancers, hasn't changed all that much; half the musicians on the roster were in the group a decade ago. But they're now playing with a youthful edge, finding threads of novelty in some of the world's most familiar music.

The guiding spirit of Mostly Mozart 2.0 is Louis Langree, who took over from Schwarz as music director in 2002, having made his name at the Glyndebourne Festival. An amiable-looking fellow with tousled hair, Langree conducts in a collarless white tunic, which makes him look something like a celebrity chef. His style is at once warm and sharp; he is plainly liked by the players, yet he is able to steer them out of the eddies of harmonious routine. He has a neat way of etching the beginnings and ends of phrases, so that Mozart's heavenly paragraphs don't devolve into dulcet murmuring. In the first movement of the "Haffner" Symphony, for example, a pattering eighth-note figure at the end of a measure is given a marked articulation, so that it drives into the next bar with a kind of piston action. In the same movement, upward scales in the strings are dramatized with quick, flaring crescendos. All through the scores, decorative details become pulses of energy, flexings of musical muscle. At the same time, Langree avoids the bad habit of incessantly poking at the music as if it were almost dead.

The theme of this summer's festival--it ends on August 27th, with the Mass in C Minor--is "Travelling with Mozart." We follow the composer on various revenue-generating trips to Paris, Prague, and London; we sample music from each country and hear Mozart's works interpreted by native ensembles and soloists. At times, the attempt to keep the governing theme afloat results in awkward intellectual calisthenics. When the Gabrieli Consort of London, under the direction of Paul McCreesh, played Mozart's great G-Minor Symphony, the program annotator ventured that the work was somehow English in nature. I'd have guessed we were in Italy; the performance was winningly fleet and graceful, devoid of the Romantic histrionics that conductors sometimes bring to this piece. Mozart was, in fact, music's perfect cosmopolitan: wherever he went, there he was.

The festival also wants to shake up conventional patterns of programming, in an effort to simulate the wildly varied concerts of Mozart's time. In the opening weeks, concert and opera arias enlivened the usual procession of overture, concerto, and symphony, and a handsome parade of sopranos delivered them. Renee Fleming, who sang at the opening-night gala, gave evidence of having headlined one gala too many: she rendered a group of Handel arias in an unintelligible, mannered style. The diva-in-chief was followed by a posse of younger women who were determined to make an impression. Emma Bell sang Mozart's "Ah, lo previdi . . . Ah, t'in-vola agl'occhi miei" with gleaming intonation and a buoyant ...