WGBH in Boston is showing a Great Performances program called Three Pickers - Legends of American Music. Also, Detroit's WTVS is showing the same program on July 28th. Both channels will repeat the show.

Here is the PBS synopsis of the program:

The Three Pickers: Legends of American Music

   Banjoist Earl Scruggs, guitarist Doc Watson and mandolin player Ricky Skaggs join to perform bluegrass classics including Blue Moon of Kentucky.

Should be a memorable program.

WTVS also has a program called Tony Brown's Journal on July the 28th at 3:30AM which is called the Roots of Music. The PBS synopsis of that says:
The oral tradition of the slavers' African heritage