Bob Dylan covered an old blues song "In My Time Of Dying", also titled as "Jesus Make up my dyin' bed" or some other variation when performed by delta bluesmen. I'm not sure the real author of the song is known, although it can be traced to a few guys. I also have the Blind Willie Johnson version as well, but can't really say which is better because they aren't in front of me now.
http://en.wikipedia.org/wiki/In_My_Time_of_Dying
Led Zeppelin later covered this on Physical Grafitti, turning it into a hard electric blues jam. Phenomenal performance by the whole group, but Bonzo really stands out here. This is easily better than any other version.