I heard the Master Musicians of Jajouka at a Moroccan music festival several summers ago, and then visited Jajouka to do a radio piece about them. Rather than try to describe their really entrancing music, I'll just direct you to their website.
At Jajouka Issandr and I met Bashir Attar, the strange and funny and very rock'n'roll head of the Master Musicians of Jajouka (it's an inherited position, from father to son). We were his guests for one long day and night. We wandered the village (which has spectacular views and no running water), looked at all the pictures of Bashir with various visiting foreign musicians, listened to him tell a lot of rambling stories, had dinner (a whole goat was killed for us--we were served at about midnight, outside, under a full moon). All evening people trickled in, musicians and young men from the village who sat smoking kif pipes--and then people started humming, tapping on tables, and instruments started appearing one by one, and at about four in the morning some great music was played. It was a memorable night, to say the least.
The article mentions that today there are two groups billing themselves as the musicians of Jajouka (you can see from the comments that this issue remains a contentious one). Clayton makes a good point that "One of the defining aspects of folk music is openness: if you can play it, it’s yours. Like speaking a language, the ability to perform unwritten music confers – is – its own legitimacy. But the two groups lay claim to the same list of recordings, the same history of musical collaborations, and certainly these are facts that can be established. The two Jajouka bands is a complicated story, involving a split of some sort within a fluid, multi-generational musical tradition (and the pressures and enticements of a Western market). As far as I can tell, Bashir's group (or his father's) is the one that did most of the famous recordings and collaborations, and that's invited to festivals, etc. That doesn't mean other musicians from Jajouka are "inauthentic," as Clayton points out. But to raise this issue and then dismiss it as beside the point--without doing a bit more research, without comparing the music put out by the two groups, without bothering to talk to the musicians themselves--seems a bit facile.