I believe in keeping things as simple as possible! I also believe kids are most engaged when they are having fun. Most of my readers' theatres are cross-curricular, combining Language Arts with math and science outcomes.
My own 'go to' resources are Bennett and Rolheiser's Beyond Monet, Kagan's Cooperative Learning, Wheatley's Coming To Know Number and Jeanne Gibbs Tribes learning processes. These books are dog-eared and worn on my shelf!