I've been using a book called "Kid Power Grammar" in my afterschool classes for some of my more proficient classes (3rd, 5th, & 6th grade).  It's gone quite well, despite being a little more "work" heavy than the way some afterschool classes are taught, and the kids are showing significant progress.  So, I've decided to post my lesson plans and materials online.  I don't have time to post everything right away, but I'll update as I have time.

You can find the book all Kyobooks and many other book stores in Korea, though if you want to buy copies for all your students, you'll probably have to order of GMarket of something.  Otherwise, you can just buy the book and make photo copies.

I use the book for class, and the workbook (bought separately) as optional homework (which they get candy for if they complete).

Generally, I break each lesson into two sessions, each about 50 minutes in length:
1. The first session introduces example language to demonstrate the grammatical concept being taught.  I use the example sentences from the "Kid Power" grammar tables in the book, but supplement them with images in the PPT to ensure that students understand.  I have students read the sentences as a class.  Then, as a practice exercise, I have students complete the "Kid Power Practice" and "Kid Power To Speak" exercises.  At first, I'll ask for volunteers to answer each question, but as students catch on I start picking students at random to keep students on their toes.  As students complete each sentence, I then have them read the completed sentence.  I also use graphics in the PPT for each sentence to ensure that students associate the sentence with its meaning.  Once those two practice exercises are done, I do a game or two to reinforce what they've learned.
2. In the second session, I have kids complete the "Kid Power To Write" and "Kid Power To Think" exercises, calling on random students and having the class read the completed sentences.  If time allows, I do a game, and then give the students a journal writing assignment where they have to use what they've learned to complete some open-ended but short writing assignment.

Sometimes, I do a third class in between 1 & 2 and fill in more games if I feel the students need more practice.

Note that the materials for the earlier lessons are quite as polished as those for the later ones.  Also, the PPTs are actually made with Keynote (Apple's presentation software for Mac), and the exporting the files to PPT sometimes moves things around on the slides or causes other problems.  So, if you have any problems with the PPTs, please let me know so I can fix them.

Link to book:
http://item2.gmarket.co.kr/Item/detailview/Item.aspx?goodscode=612745633

I recommend skipping "Start Power Practice" on this one.  The activity was too difficult for many students, and didn't really contribute much to the lesson.

Review lesson for Unit 1 on nouns.

The PPT exports were too garbled in this case, so I exported the presentations as HTML and put them in ZIP files.  You'll have to unzip them to a folder and then open the index.html.  I recommend using Windows Explorer to open the zip file (right click -> open with -> Windows Explorer), not whatever your Korean computer uses as the default for zip files (some don't unzip the files properly).  When you open the presentation in your browser, you can use F11 to toggle to full screen.

This lesson adds "we" and "they" to the list of pronouns students learned in the previous lesson.

For the writing assignment, I had students make a comic.  I provided them with an example, but encourages students to be creative and make up their own (students so often think I just want them to "copy" what I've done...groan).

Review lesson.  I only created questions for the first round of the Mario template.  The started on the second round, buy they are incomplete.  The first round was enough for a 40 minute lesson, though.

I found in this review that students had the subject pronouns (I, he, she, it, they, we) down pretty good, but still struggled with this, that, these, and those.  So, I made a simple review presentation to quiz students on this, that, these, and those as a warmup in my Unit 3 lessons.

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I'm glad it's useful to someone.  There's more coming, but there's a lag because I have to organize all the materials before posting them.  If you or anyone makes new stuff for these lesson, please post them, because I don't always have time to make as high quality of stuff as I'd like.

I didn't think my students would like "grammar" lessons much either, but I've found the students are actually quite engaged and is by far my most successful framework for planning lessons.  The students seem to enjoy them most of the time (more specifically, they usually enjoy the games and will at least willingly play along with the presentation and practice exercises that come first).  It helps that they're pretty good students to begin with.  In my case, I only teach the grammar lessons to those classes that already have a good handle on the curriculum classes.

Part of what i think make these lessons work is they spend very little, if any, time talking about grammar, and instead focuses on giving tons of comprehensible input, which is exactly what they need to acquire the grammar.  Throughout the class, every student is getting drilled to read/comprehend, speak, write, and listen to examples of the target grammar point, and it does become clear over time that they're improving and better able to put sentences together as a result.

I also think teacher grammar is a good compliment to the grade school curriculum, which focuses too much on vocabulary and only teaches very situational "grammar."