I love the book First Language Lessons for the well trained mind by Jesse Wise. Lilah and I worked in it every day when she first came home. It is basic grammar taught in a fun, hands on style.
I believe that many of these lessons can be easily adapted to fit the older child who needs to review or how has just been introduced to grammar.
We began writing group with a review of verbs, specifically linking or helping verbs. The girls were given the directions to cut out two or three pictures from magazines that they found interesting. They glued the pictures into their journals and wrote a sentence about the picture. They were introduced to the concept of diagramming a sentence by boxing the verb and the helping verb.
A list was added to their journal. They discovered on their own that the helping verbs changed depending on the tense of the sentence. To vary their sentences, they used different tenses.
It was a fun mini-lesson adapted from First Language Lessons.