This door conceals the A/C unit.
In our house, we use a small, magnetic chalk board to keep track of grocery lists, phone numbers, and items that can be easily forgotten (thank-you notes, usually).
So here we wanted the same.
Unfortunately, it turns out that magnetic paint doesn't really work. I mean...it works ok. You can get the magnet to stick to it. But if you wanted to stick something to the door using the magnet? Not really.
Chalkboard paint, though? That stuff is great. Two days of modest craftiness (as in: paint a coat, go on with your life, six hours later paint another coat, go to bed. Next day: pull off the tape and enjoy!) yielded a great surface for recording our schedule and to-dos.