The calendars are printed 2-up to fit CD jewel cases -- the output PDF contains a photo of the actual physical output (the bigger one). Can now be compile with xelatex (updated Dec 18, 2018).
Colours, illustrations, fonts etc are customisable. The calendars can be marked with events with date ranges, with different markers and styles (updated Dec 18, 2016).
Use the sundayweek document class option to make weeks start on Sundays. (updated Aug 3, 2015).
Localisation possible with languages supported by babel/translator/datetime2.
Tested with british, spanish, french, ngerman, italian, portuges, polish, croatian, greek. Use the nobabel option and make your own customisations, for languages not supported by babel and/or translator (Dec 18, 2016). Here are examples for Chinese and Japanese.
Note: If you get an error when you change the language, click on the "compile from scratch" option in the error message window.
The corresponding calendar to fit into a 3.5" floppy disk jewel case can be found here, while a full-page "giant" version can be found here.
Or fork it on Github!