Upbeat instrumental folk music: recommendations?

I’d like to put together a fairly long playlist of instrumental music, cheerful and lively but not obtrusive, to serve as background atmosphere for a social event. I’m interested in recommendations that include links to a sample so I can audition them.

Yes:

— Celtic-style music, but not excessively Irish—maybe more of a Scottish flavor, but not excessively excessive in any case
— traditional American, except as below
— modern compositions and ensembles that echo and reflect traditional styles
— stuff like this and this

No:

— bluegrass
— country & western
— classical
— downbeat; slow; moody; romantic; dark & stormy
— banjo-heavy; very twangy; super-bouncy jigs & reels
— jazz
— any vocals
(I like all those styles—except C&W—but they’re not the tone I want for this event)