As a class, brainstorm a list of words to describe a topic (ex: Spring). Divide the class into small groups (3-5 kids) and give each group one sheet of paper.
Each student will write a sentence using one word from the list to create a stanza for the poem. Depending on ability, they can make their stanza rhyme, or you could have them make a stanza, a cinquain, haiku, etc.
Each group shares their stanza with the class and the teacher writes the poem on chart paper. My sixth graders really like this activity. We do it for each season, different holidays, and events.