Center for Computational Astrophysics (CfCA) is a branch of National Astronomical Observatory of Japan (NAOJ) and provides computational resources for astrophysicists. To use the resources, you have to submit a scientific proposal to CfCA. The application form for the submission is available from here.
Customisable calendars supporting different languages, sizes (normal, "giant", "giantlandscape" and "small"), colours and illustrations. The calendars can be marked with events with date ranges, with different markers and styles.
The default-sized calendars print 2-up on A4-sized papers and should fit CD jewel cases.
The "small" calendars print 4-up on A4-sized papers and should fit 3.5" floppy disk cases.
The "giant" calendars are full-page A4-sized.
Colours, illustrations, fonts etc are customisable.
Use the sundayweek document class option to make weeks start on Sundays.
Localisation possible with languages supported by babel/translator/datetime2.
This is an example of such a customisation for Japanese, to be compiled with LuaLaTeX. The original templates will work with language options that are supported by datetime2 and babel. Use the nobabel option and make your own customisations, for languages not supported by babel and/or translator.
Note: If you get an error when you change the language, try clearing the auxiliary files in your compile session.
Or fork it on Github!