The big wheels at Denver International Airport have done plenty wrong over the last year, but here's something they did right: They allowed the International Performance Series to continue inside the airport over the Christmas holidays, despite the post-September 11 security concerns that forced them to cancel it during the Thanksgiving rush. For more than a decade, musicians have roamed the concourses at DIA (and Stapleton Airport before it) during the hectic times of the year, entertaining travelers and easing the minds of anxious or delayed passengers. The variety of performers has been wide, with acts including Banda Felicidada, Camacho-Ransoli, Bill Barwick and Sons of Tumbleweed, and Boxty, a Celtic quartet, as well as city auditor and presumed mayoral candidate Don Mares, who performed as part of a folk duo. The series is managed by Meredith Gabow, who also runs a companion Web site at www.calmthebeast.com. For her dedication, and for DIA's decision to resume the series, we offer a joyful noise.