Featured 4:00 pm - 7:00 pm COS 55th Annual Spring Concert Featured June 15, 2024 @ 4:00 pm - 7:00 pm COS 55th Annual Spring Concert COS’s annual end-of-season concert featuring performances by all COS orchestras, Elite String Ensemble, Wind Symphonic Ensemble, Percussion Ensemble, and Mallets & Bars Ensemble. $28.50