My second grade kiddos have been working on subject and predicate which can be pretttty tricky! To make it a little more understandable, my students made subject/predicate puzzles. Then they took their subjects and walked around to each desk and made silly sentences with the other students' predicates. The kids LOVED it.
Have kids draw/paint their own planets/stars first, then while they dry they can work on the starry background with crayons, light colored pencils, paint. Then cut out the stars/ planets and glue on. They can also add aliens/astronauts/spaceships.