GUEST,Lyle is not biased!
The Walnut Valley Festival is a real winner. I've been going for 1986, with only 3 years missed when I was in the far Northwest.
Lots of people refer to it as a "bluegrass" festival, but it's not. Officially it's an "acoustic music" bash, with International Championship competitions in several instruments and very high level "showoffs" in others. Flat pick and finger pick guitar, mando, fiddle, lap dulcimer, hammer dulcimer, autoharp, banjo - you name it.
The competition is fierce to get good camping spots, so a good many of the folk show up and beat on the gates until they let 'em in.
Nearly two full weeks of campground pickin' so good most of us seldom go to any of the 6 stages to hear the hired talent (which is very good). We mostly leave that for the "day pass" people.

John