I keep all of my important appointments in a Google Calendar. I also write some of them on paper too just to have a visual reminder when I sit at my desk. If you use a similar system, you might be interested in these free printable calendars. From the website you can print calendars for any month of the year in 2012, 2013, 2014 and beyond. Just select the month and year then click print.
Applications for Education
If you need some paper calendars to distribute to students or if you just want a calendar for your desk, these calendars are for you. In an effort to recycle, I printed one for December on the back of some scrap paper.