I recently heard (on the radio) a great one by Bill Withers, famous for "Ain't No Sunshine," "Use Me," "Just the Two of Us," etc. I'm almost positive it dates back the the Vietnam era (as do Bill's hits) but it's something I don't remember ever having heard before.

It was a live recording (audible audience reaction) with a long spoken introduction, about visiting a veterans hospital, meeting with wounded and disabled returnees from Nam. He stops speaking and begins singing after starting to tell us about one amputee, who asks Bill to write a letter to his mother. The title (and first sung lyric):

"I Can't Write Left Handed." Very powerful stuff.