One day I might get the big flip one but in the meantime I made a chalkboard clock/calendar. Which I also love because I get to cross of the days as I go, so satisfying. The frame is from Ikea and it around A4 sized, without the cardboard border insert, and the clock mechanism was a cheap Ikea clock. These frames are lovely but the only thing that annoys me is that the little metal rectangles that fold over to keep it secure are flimsy. Meaning you can't really change your artwork as the metal things will snap off. As I knew my clock would be staying put I glue gunned it in place.
It was really easy to make; painted the wooden frame insert with chalkboard paint (two coats), painted on my calendar grid with acrylic paint, made a whole for the clock mechanism and put it together, then wrote the dates on with chalk. Done.
I got the chalkboard paint especially for this and got the smallest tub I could find. Even then I had loads left over, so I then made the second thing to write 'to do' lists and then easily hide it by flipping it over. I still have loads of paint left. Need to find something else to do with it.