I don't know if I would teach grammer as a unit, by itself, but rather I would integrate it into mini-lessons that have a different major objective. Does that make sense? Inotherwards, I can always incorparate grammer when I teach a book or something. I will just incorporate different mini-lessons as I teach the main unit.
Growing up my teachers would just give me worksheet after worksheet and I really don't think I learned anything! Also, it was extremely boring and I didn't want to pay attention! Granted, I know how to make a complete sentence and I can write a decent paper, but I don't know the terminology for different parts of the sentence. Therefore, I think it is best to integrate grammer into lessons, but I do feel that it is a bad idea to teach grammer by itself!!!