A little backstory:
I do all my work in Algebra II on a SmartBoard. I always post PDFs of each day’s notes for students to download if they want to refer to something. A few times a week, a student will ask me — when I’m moving to a new page of the SmartBoard — to go back so they could finish writing their notes. I’d say almost every time I go back and let them finish. But sometimes I have to move on in the lesson, and the student asking decided to write things down after the material has been on the screen for a few minutes already — right when we’re done with that material. In those cases, I say “I’m sorry I’m going to go forward, but remember, I always post the SmartBoard.”
Now the story.
Yesterday I was in Algebra II and we were working on optimization word problems (find the maximum volume of box with some constraints on the sides, find the minimum cost to make a box). I realized I had been up at the SmartBoard too much recently, so I called on a student to be “Teacher.” I told the student that she had total control — so she needed to ask questions, answer questions, and keep all our miscreant compatriots in order.
She started working, and doing a fabulous job. She fielded questions like a champ. At one point, she moved from one page to the next, and someone asked if she could go back to the previous page.
She looked at me, at the student, at me again, got the smallest smile on her face and said:
“I’m sorry I am moving on. But I post the SmartBoard every night.”
The whole class broke into laughter. I laughed. And laughed. I couldn’t stop laughing for like an entire 60 seconds. Classic.
I like that class a whole lot.
(And indeed, after the laughter subsided she didn’t go back to the previous SmartBoard page, but kept on working.)
Continuous Everywhere but Differentiable Nowhere 
Imitation is the sincerest form of flattery, friend. I especially appreciate the fact that she stuck to it and kept going. Where do you post your .pdfs? I’m thinking about doing something like that in the future for my classes, but unsure where to post things that will be accessible to the students.
I post them on something called a “course conference” in a system our school uses called “FirstClass.” But if you don’t have that, just throw them online using something like box.net, I say.