And then I remembered this:
My boss/neighbor gave me this mirror one day as I was leaving. Her friend had given it to her, but she didn't know what she'd use if for. I told her I didn't need it, but I was in a rush that day, and she insisted. I left it in my basement to start collecting dust.
I decided to try the chalkboard paint out on it. So while the kids slept, I quickly threw scotch tape around the white part and did the first coat:
Throughout the day, I added on to it two to three more times (by the fourth coat, I was good). By the night, it looked like this:
I took some sand paper and sanded away a bit at the frame to take down the glossiness. Then I mixed together some cheap acrylic paint and painted around three coats.
So this morning, it looked like this:
Then I measured it out. I made a mark three inches from the top and then three from the bottom. In the middle of the two marks, I made another. Then I used a straight-edge (yes, that is the Sims, and it was mighty handy!) to bring the lines all the way across. I made sure to only use dashes for the middle line.
Then I used awesome concentration to go over the lines with white acrylic.