Dunegrass Music Festival

Now "Sleepy Bear Music Festival" for 2012.
The festival used to be bluegrasss music, but now it's kind of general-purpose acoustic and roots music.

Near the little village of Empire, Mich. At the edge of the Sleeping Bear Dunes National Lakeshore. So you're camping in the woods near the beach, with a free shuttle to the beach, and the kids can play in the sand and jump into Lake Michigan.