I actually taught a friend grammar last school year. I found it easier to teach her rules than to correct the errors in the papers she had me proof for her.
so, okay. how did I do it? Schoolhouse Rock.
no, really! I played, for example, "Rufus Xavier Sarsaparilla," and then, we'd go over pronouns in more detail than can be managed in a three-minute cartoon. she had this little notebook that she wrote it all down in, so if she needed to refer to it, it was all in one place. is her grammar now perfect? oh, good lord, no. she's still got a tin ear for using contractions. but she knows how to identify a prepositional phrase and a complex-compound sentence, and isn't that more important?
I even taught her things I knew she probably already knew, because I'd rather be sure than get into compound sentences and discover that she didn't know what a conjunction was.
I'd offer to teach anyone else who wants to learn, but, well, you'd have to come to Olympia. I could probably work something out online, if anyone's interested.
"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"
"You can't erase icing."
"I can't believe it doesn't work! I found it on the internet, man!"