On Sunday, the Chicago Sinfonietta played a new work with unusual instrumentation: the world premiere of the Concertino for Cellular Phones and Symphony Orchestra. During the performance, audience members were signaled to active phones by the illumination of colored lights — red for the balcony, green for the orchestra seats. The Sinfonietta's Music Director, Paul Freeman, discussed the work in the context of music with random elements, including pieces by John Cage and Charles Ives. However, the October 1st premiere was highly organized; the orchestra provided directions via email and in the program, and the conductor held a practice session before the performance.
To get a flavor for the music, you can view the Chicago Sinfonietta's television commercial featuring the Concertino.