A Google calendar with the entire family's schedule (plus my major assignments/tests), so I can see just how crazy my life is from anywhere I might happen to be. (School was a helluva lot easier when I didn't have kids' dentist appts, softball games, after-school socials, etc, to think about.) I also print this calendar each week, and we have a family "meeting" to go over everything on it, so everyone knows where everyone will be.
A whiteboard wall calendar with all my major assignments for the entire semester, so the family knows when I'm more likely to be a stress-case and avoid me.
A whiteboard refrigerator calendar with the family's non-routine events so everyone can see at a glance when the schedule will vary. (This does not duplicate the printed Google calendar, because it is for the month rather than the week.)
A spreadsheet showing all my assignments, readings, tests, quizzes, papers, etc, organized by due date. This one is especially satisfying 'cause I can check things off. (I love checking things off. I'm one of those people who writes "Write list" at the top of my lists, so I can immediately check something off and get that feeling of satisfaction from getting something done.)
Plus I have all the syllabi, which I check regularly to make sure I'm not missing anything. And now, since creating more calendars would be overdoing it a bit (don't you think?), I am writing about my calendars. I find a certain comfort in them, like they are my security blanket. I think what they illustrate more than anything, though, is that I will need a long vacation with nothing to do but lie on a beach once this semester is over.