I'd like to speak up for the use of literary materials as illustrations of
grammatical concepts, and grammatical terms and methods for the analysis of
literary materials.  I've gotten good results by asking students (including
ill-prepared students) to find the subject and predicate of the first
sentence of a poem, for example.  In a literature classroom, questions of
grammar (pitched at the right level) are often much less intimidating than
questions about the meaning or effect of a difficult text.  And in a writing
classroom, poems and other literary works can excite more interest than the
often inert sample sentences of grammar texts.
 
Jim Barszcz