Chalkboard

Did you know you're supposed to "prime" a chalkboard before using it? (No, neither did I.) Scribbling all over it and then erasing is supposed to leave behind a thin coat of dust that encourages the chalk to adhere. I quickly gave up on that — the eraser wasn't really working (there's a slight texture to the ceiling), and I had to use a damp cloth to erase my scribbling, but then you're supposed to prepare the chalkboard all over again after cleaning it with a damp cloth. And I was getting chalk dust all over everything. And the chalk seemed to draw just fine.

In case you didn't recognize it, that's a picture of Jupiter (with the Great Red Spot in the bottom right corner).