In an earlier blog, I encouraged some Haiku writing. Here's another fun resource from Scholastic called the Poetry Idea Engine which introduces styles of poetry in a fun and palatable fashion.
Another site to investigate is ReadWorks, a free site with reading comprehension resources - although registration is required to access the resources. I note that the academic advisors include Benchmark friends Freddy Hiebert and Joanna Williams, so I have some confidence in the site materials, although I haven't explored extensively. Specifically I wanted to highlight their National Poetry Month page, which contains downloadable poetry and discussion questions by grade level. I would also recommend the section on Figurative Language, with lesson plans and sample stories by grade level.