I had trouble getting students to sit down and write an entire poem on their own. This activity helps them to get used to it.
Break students into medium groups (6 to 8). Each student gets out a sheet of paper. Each student gets a 3"x5" index card with one word on it. you will have made these cards up ahead of time. Put words such as sun, love, tree, river, blue, flower, kitten, etc. on them. Basically anything that a student can write a poem about should be a "topic". Each student looks at their card and then must write one line about their topic. Encourage them to use some of the poetry terms that they know.
After each group member has written a line about their "topic" each member passes their card to the person on their right. That person will read the first line and will write a second line to continue the poem. The line must relate to that specific poem and must continue the poem. After each member has written their line, they will pass it again to the right. Eventually, the poem will make it back to the owner. The owner will finish the poem with a final line.
So, the result is that each member has a poem about their "topic". Each member has contributed one line to each poem. This is a really great activity and I have had much success with it!