Here's a fun, easily implemented, success nearly guaranteed but my boss won't let me put it in writing, creative writing activity for elementary educators and homeschool parents/guardians.
Stop That Poem! (Kane Miller Books) sends a poem on a flight of adventure: dropping into a lake, soaring over a city, blanketing a community garden... You can expand this story with new ideas.
Read the story with your students. Discuss all of the different places the poem travels. Now brainstorm. Where else can this poem go? What else can this poem do?
With the youngest students, adding single lines makes for a terrific goal. Use this as an opportunity to work on similes (...might roll in the mud like a little pink pig) and descriptive writing. Guide the students toward selecting the most appropriate verbs (drop, glide, roll...) and the most effective adjectives.
Older students might work toward creating rhyming couplets. Be sure to keep pushing toward strong word choice and similes.
Finally, use these new ideas for an art and writing project. Let the students copy and then illustrate the new sentences. They might even write each word in a little box like they appear in the illustrations from the book.
Stop That Poem! is available through your favorite Usborne Books and More consultant. Or visit KaneMiller.com