Take Sunday night at the Rudolfinum, which opened with a performance by one of Europe's premier modern music groups, France's Ensemble InterContemporain. Founded by Pierre Boulez in 1976, the chamber group was led in its Prague appearance by Romanian-born conductor Peter Eötvös, who has been with the group on and off since 1979.

It's hard to remember a smaller group making a bigger impact. The opening piece, Boulez's "Le Marteau sans Maitre," featured just seven musicians and an alto singer, Hilary Summers. The performance was precise yet warm, not an easy task with such cerebral music. The audience — a lot of tourists, but a core of local modern music enthusiasts — hung on every note, and was generous with its applause.

The second piece, Arnold Schönberg's "Pierrot lunaire," had just six musicians (with two doubling up on separate instruments) and Summers in a choice role — the piece is a showcase for the singer. Summers had a wonderful feel for the material, bringing great expression and clarity to complicated phrasing, with some nice touches of humor. The audience responded with wild enthusiasm, bringing her back out for six curtain calls.

Music of that difficulty and caliber doesn't get performed in Prague very often, much less letter-perfect by virtuoso players. The applause and yells of "Bravo!" were over the top, but in this case, well-deserved.

Following the French recital, one of the world's greatest pianists, Emanuel Ax, unpretentiously took the stage for Prague Spring's successful new series of late night shows, which it calls Nokturnas. Performing a stunning recital of Beethoven and Mozart pieces, Ax's specialty, the diffident maestro responded to thunderous applause simply by standing back from his grand piano a few steps, taking a shallow, formal bow, then resuming his playing.

Clearly the idea of late concerts, like the midnight movies that now run at film festivals including the upcoming Karlovy Vary International Film Festival June 30–July 8, is a hit. Although attendance has been low in the past for Nokturnas, audiences packed the Rudolfinum for Ax's Sunday night. His Chopin piece, Nocturne in D flat major, seemed just the stuff