Originally I came across the calendar design on the Canon website in 2006. But, after looking at my 2 page vertical calendar for a few months, I decided that if would be more convenient to have it all on one page. So I changed it to have the whole year on one page. I create the basic template in MS Publisher and then update it yearly.
Download the PDF file and print the 2nd page at 100% on cardstock.
Assembly instructions are on the first page.