What are some strange, weird, odd, or funny facts you know about calendars?

There was once a Ford dealership entitled 'Dick Calendar Ford'. This post was edited by B.H.Wilson at January 7, 2020 10:26 AM MST

They repeat themselves every 28 years (and every 11 years in non leap-years).

When I was young, the phone book contained a perpetual calendar (good from 1900 all the way to the futuristic year of 2000).  Tack it to the wall and one would never had to get another calendar at the end of the year (even though in those days calendars were free at every store - and they were fancy).  

.....they are very popular .....always going out for dates....

There are forty different calendars used in the world today.  Most of them are used for religious purposes.

The first centerfold picture in Playboy was Marilyn Monroe.  This picture was originally taken for a calendar not for a centerfold. 

https://www.google.com/search?q=Playboy+calander+history&oq=Playboy+calander+history&aqs=chrome..69i57.11423j0j7&sourceid=chrome&ie=UTF-8 This post was edited by Merlin at January 7, 2020 10:50 AM MST