The old girl is weakening fast, and never really lived up to her advance billing. Before she goes, a musical farewell:The Willie Nelson version of "Goodnight Irene," is my favorite, so far, video-wise. But Tom Waits is inimitable, and Johnny Cash the same, if only in soundtracks.And Lead Belly's version is considered the "original," though the song's origins seems murky. But the story associated with it is the best. Lead Belly (or Leadbelly), a.k.a. Huddie William Ledbetter, was serving one of his many stretches in Angola prison in Louisiana in the 1930s when the Lomaxes "discovered" him and recorded him. The legend has it that he included a recording of "Goodnight Irene" with his petition for release and that the warden said any man who could sing like that shouldn't be in jail.Or something like that. It's apocryphal, but as we say in the tabloids, it's too good to check out. So go with it.