Never fear that the blues are dying out. Shemekia Copeland, still in her 20s, has long moved beyond upholding daddy Johnny Copeland's legacy. She is singing and shouting so sassy and proud, he's got to be hearing her in the next world. (Sunday)

Young musicians, ages 6 to 17, are often closet folkies. Not because they want to be in the closet; there just aren't any peers to jam with. String players, percussionists and whistle or flute players are encouraged to bring their instruments to get woodshedding with Groovemama for three days. After all that learning and practicing and jamming, these acolytes will have a grand festival debut as the Great Groove Band on the main stage on Sunday afternoon. How many lifelong musical partnerships will be formed? Only time will tell. The mentors in Groovemama are some serious players (Jane Rothfield and Donna Hébert, among them). (Sunday)

Huun-Huur-Tu from Tuvan, Southern Siberia, practice the type of overtone singing that guys alone with a flock of sheep or reindeer had time to perfect. You'll either love them because the sound is so compellingly non-Western or hate them for the same reason. (Saturday)

Raul Malo's smooth singing gives goose bumps. OK, his success with the Mavericks may make him too popular for the purists. But if this were a record hop, RM would be the ladies' choice dance; know what I mean? (Saturday)

Dermot Hyde and Tom Hake, aka Pipeline, are exquisitely well-paired on pipes and strings respectively. They do justice to all the Celtic styles with good humor and energy. (Friday)

Alex DePue is that rogue fiddler you've heard about. Rogue in that he prefers to play swing and bluegrass over the classical playing for which his family is famed. (Ask him how many orchestra members there are among his sibs; I've lost count!) Putting that classical touch and tone to the service of rhythmically compelling music leads to some breathtaking playing. (Saturday)

—M.A.

Yes, this is the same Horse Flies whose music was used for Rock the Vote, who have collaborated with Natalie Merchant and whose members continue to churn out soundtracks for films like Disappearances (with Kris Kristofferson) and The Cultivated Life (a PBS documentary on Thomas Jefferson's interest in wine). They will be on the Philadelphia Folk Festival's main stage Saturday and in the dance tent several times throughout the weekend.

As young adults they found old-time music's attraction so strong that they made time to head south to three or four major music festivals every summer for well over a decade. "Quite a schlepp," recalls Claus, but worth it for the chance to immerse themselves in the music.

Proficiency in old-time did not mean that Hyman and Claus were interested in keeping it discrete from other musical tongues. "We play creatively with traditions. The traditional roots are something we admire." He continues that when they first started this experiment, "There were people who found it disrespectful. But we wanted to play the music we'd been influenced by. Old-time was one thing, but we've listened to African music and loved that [and] new wave and minimalist and rock. I listen a fair amount to alternative new stuff."

"We love a groove," says Hyman, whose dark curls really fly when she digs deep into a fiddle tune. "We're very rhythmic and we love to stretch out."

Hyman adds, "We are not eclectic." A strange thing for an accomplished hybridizer to say. She elaborates, "We are not genre-switchers! We are just trying to create an expression of who we are." The important point is that the Horse Flies have an identifiable sound, which includes her violin with effects at the ready and Claus' assortment of strings from banjo uke to electric guitar, again all eligible for a stomp box change at a moment's notice. Banjo, bass, accordion and ethnic percussion add plenty of drive to the Flies.

The Saturday show should be a treat, but this music is meant for dancing. Hyman is particularly enthusiastic about their scheduled collaborator in the dance tent. "Beth Molaro is my favorite caller to work with. Dancers love her for the funky way she leads them."

(m_armstrong@citypaper.net)