My neighbor Pete loaned me a couple of DVDs called "American Folk Blues Festival".  They are composed of footage recorded in Europe when blues artists were touring in the mid--1960s.  Evidently the film was misplaced and then rediscovered after gathering dust for 40 years.  The quality is awesome.  If you love or even like the blues, you will want to see these sometime....

PS:  The attached photo is a young John Lee Hooker, the original cool cat.