Because writing is so very important in high school, college and beyond...I think giving your kids a solid foundation in grammar will only help them. Even the best spellcheck/grammar check cannot truly know how we mean a sentence to be. If we know the rules, our creativity will be a choice and not a deficit.

I don't have any good teaching resources. I always LOVED sentence graphing (especially once it became quite complex). It felt like a nice juicy logic puzzle. My DH, on the other hand, detested it.