I buy the Flylady calendar.Since I started buying that one, I have not bought any others and have told people NOT to send me a calendar as a Christmas present, because it won't get used. The Flylady calendar does not have pictures on it, it just has large squares where you can write any appointments or anything you need to remember. It acts as a diary for me and hangs where everyone can see it. If they want me to do something for them (like babysitting) they check the calendar first to see if anything is written down there. If it is, they don't bother asking, (unless it's an emergency of course).
It is A3 in size and when it is hung up, it gives you two A3 pages hanging for one month. Plenty of space to write anything. I keep a record of the meals we have had, so I don't repeat them too often or to get inspiration for later in the month. Our dental appointments for next May 2013 are already written in.
How's that, you may ask? The flylady calendar covers 17 months from August one year to December the following year, so it gives you the space and motivation to write things in well ahead of time. It's a great organisational tool and I am really pleased with it.