Model Lesson

It's been 7 years since I've taught a high school class from beginning to end.  There have been a few teacher writing workshops at conferences, and a couple of co-teaching moments in the classrooms of the student teachers I've supervised, but nothing bell to bell.
That might end in a few weeks.  In my role as a mentor teacher, I occasionally have an opportunity to model a lesson.  Trouble is, most of the first year teachers I mentor don't live close enough to me to make that possible.  One is in Alaska, another in Montana.  Still another is on the Oregon coast in a small town, and a few others have been less enthusiastic about seeing the old man in action.
This year might be different.  I've been mentoring a first year teacher close to home.  Well, fairly close to home.
A recent study I read revealed that mentor teachers modeling a lesson and then possibly co-teaching it with the beginning teacher was rated one for the most useful things a mentor could do.  It provides a chance for the mentee to see the mentor as a teacher not just a giver of advice.
There are some considerations before jumping in and taking over a class.  The mentor shouldn't necessarily teach the best lesson ever.  It's important to be vulnerable, perhaps take a risk and fail, struggle a bit so that the beginning teacher is not upstaged in any way.
Problematic?  You bet.

So, I've been thinking about what I might do that meets all the criteria and still would be useful.
My mentee has 3 10th grade Language Arts classes in her day.  I'm thinking of teaching the lesson in the first so she can observe and critique.  Then co-teach the lesson in the second class, finally she could do the lesson solo and I could critique.  Ideally it sounds fine.  We'll see.
Now comes the what to do.
I'm toying with and tweaking a lesson on writing voice that just might fit the bill.  It's fun, it's useful, it's something I think I can still do effectively.
But this time, I want to do it somewhat effectively because it's taking on another level of usefulness.  If I'm successful, I'll make a mistake or two along the way; my pacing will be a little off, and probably some of my schtick will seem stale.  If I'm really successful, this lesson will survive in someone's classroom for years to come.