Finally, something I own! I first saw this MoMA Perpetual Calendar while babysitting. The magnetic silver sphere is attached to a string and the circular frame, also magnetic, keeps the sphere at the the month while the black sphere rests on the day. No, it's not automatic, but it can hang on the wall or sit on a shelf. When I went to Seattle, I saw the calendar at a furniture shop and had to buy it. For $40, it ends up being cheaper than buying a $15 calendar every year. Plus there's a mini version for on a desktop and different color schemes.