Interesting calendars

A list of other interesting calanders

• Indian national calendar – Wikipedia
  The best calculated solar calendar in actual use, following the Gregorian leap year rule.
  Starts about the vernal equinox.
  1 Chaitra falling on 22 March normally and on 21 March in leap year.
  First month is 30 or 31 days, followed by 5 months of 31 days, then 6 months of 30 days.Weeks begin on Sunday and and end on Saturday.
  
• Solar Hijri calendar – Wikipedia
  The best observational solar calendar in actual use, so a 5 year leap interval after six or seven 4 year leap intervals.
  Starts on the observed vernal equinox.
  6 months of 31 days, 5 months of 30, and then a 29/30 day month.
  Weeks begin on Saturday and end on Friday.
  
• Leap week calendar – Wikipedia – good summary of advantages and disadvantages.
• Leap Week Calendars (hermetic.ch) – explanations of possible leap week cycles.
• The Medieval Calendar within a Deck of Playing Cards (archive.org)
  It’s a truly beautiful illustration of the Julian calendar. Each playing card represents one of 52 weeks (4×13), and the jokers represent an extra day.
• Karl Palmen’s Playing Card Calendar (hermetic.ch)
  As above, but joker for leap week.
  
• Types of Calendar (hermetic.ch) – classifications of calendars as
  lunar, solarm lunisolar, solilunar, lunistellar and others;
  based on rules, astronomical observation or astronomical calculation.
  
• Calendars New and Old (hermetic.ch) a variety of otehr invented calendars.