It’s 6 a.m., and the coffee hasn’t kicked in yet. You walk, eyes drooping, legs dragging, through security. Then you hear it: soft marimba chiming through Concourse C like a ’90s computer game, lifting solemn spirits. Rob Lewis, 63, padded mallets in hand, is just beginning his three-hour performance as a volunteer airport musician.

The PDX Volunteer Music Program, which began with a single piano placed at the base of the pre-security tower clock in 2002, is a post-9/11 initiative to make navigating the airport a less stressful experience, and one of the first in the country to use the model. The current cohort includes 27 musicians, from pianists to Uilleann bagpipe players, all dabbling in different genres—jazz to flamenco.

On paper, it’s a tough sell for musicians: perform, often early morning or late night, for several hours at a time, and get paid only in tips. Still, PDX Music is a competitive program that receives a few hundred applications per year. Lewis, who’s been at PDX nearly a decade and is one of the program’s few percussionists, says the best perk of the job (apart from the exposure to a chunk of the airport’s 20 million annual travelers) is getting to play for people from all walks of life—especially children: “Man, I see so many funny, funny kids dancing to my music with all their weird little dance moves. It makes my day.”