KSER bills themselves as "A Sound Adventure", and they certainly are that!
The format varies depending upon the time of day and the DJ. During the afternoons, when I'm usually listening, it tends towards folk and world music. They also carry the BBC World Service news at the top of each hour.
On Saturday afternoons, they were home to Madman Moscowitz, Seattle's answer to Dr. Demento. Madman's assistant Nathan is considering reviving the show in some form or another.
KSER is a local public radio station, although I don't think they're affilliated with National Public Radio.
KSER can be found at 90.7 on your FM dial.