Rhyming Words Activities (Pre-K-K)
Children identify rhyming words in these different early childhood activities.
http://teams.lacoe.edu/documentation/classrooms/patti/k-1
/activities/rhyming.html

Rhyme Game (Pre-K-K)
Children match rhyming picture cards while listening to a musical timer.
http://atozteacherstuff.com/lessons/RhymeGame.shtml

Zoo Animal Poetry (K-3)
In this activity, students carefully observe animals at the zoo, brainstorm a list of facts about the animals, and create an animal poem using the facts they have learned. (Can be adapted and used without taking students on a trip to the zoo.)
http://www.col-ed.org/cur/lang/lang59.txt

Friendly Poetry (1-3)
In this activity, children compile a list of the things they look for in a friend and then use that information to create a simple poem.
http://www.eduplace.com/rdg/gen_act/friends/poetry.html