I keep a calendar hanging on the side of the refrigerator. We color code events (I mark all my events with an orange pencil) so we know who is going where and when. We stopped missing events and scheduling conflicts by doing this. It has really large squares with plenty of room to write.
I keep a similar one hanging on the side of my file cabinet at work.
I'm trying to start using my iPhone to mark doctor appointments, etc. but often forget to check that. The main one is the one on the fridge.