Check this out:

http://www.spencerbohren.com/discography/album-info.php?cdid=39

Sixteen cuts, one song: each version demonstrates an era and/or an artist in the long evolution of American song, from work song to blues to jug band to string band to country to rockabilly, etc. etc. etc., on through the Folk "Scare" and the English Invasion.

Spencer is a great storyteller, and he takes the opportunity to show off some of his wonderful instruments, including a banjo and a parlor guitar from the 19th century. The concept alone is interesting enough, and he does it up right, creating something really interesting, equal parts entertainment and education. Great understated soulful vocals, and a pretty impressive demonstration of a wide range of instrumental styles ~ nothing too flashy or ostentatious, everything authentic and tasty.

The above link provides sample MP3s of the first four cuts. If you don't listen to anything else, check out #4.