I would also buy a couple of them. I think a twelve month calendar would be better for two reasons. One, it would cost less (I assume), and secondly, we wouldn't have to duplicate writing birthdays, anniversaries, etc. in both calendars the next year for the six over-lapping months. I buy a Las Vegas-themed calendar every year through eBay and usually spend $15-20. I think it would be a huge success every convention. I'm not sure about anyone else, but I prefer a calendar that has ample space to write birthdays or appointments on the date. Some are designed where there is no room to write anything, or they have a dark background that prevents you from seeing what you've written. Just my ideas.