Searching for info from past episode

I am hoping someone out there can help with this, but I'm afraid it's
a pretty obscure description.  I am looking for the name of an author
(or the name of the book), who appeared on Letterman's show, some time
during the writer's strike (we think).  What my boss remembers is that
the author read an excerpt from the book, and it was funny.  What he
remembers about the excerpt is that it had to do with a homework
assignment to write a poem, and the author chose to write the lyrics
to "The Boxer" by Simon and Garfunkel as his poem.  The teacher liked
it and made him read it out loud to the class.  When he got to the
chorus, everyone joined in singing.

That's all I got my from boss, but I told him I'd see what I could
find out.  Any help is greatly appreciated.