The calendar we use is archaic, cumbersome and a inefficient. The International Fixed Calendar offers a fix. It is a logical and easy to transition to solution to our current calendar. Though I do not expect it, I would love to see this transition within my lifetime.
Disclaimer - Where you see them, the added holidays are not necessarily correct. Many would need to be set by a governing body or religious leaders and therefore may not be accurate.
Under Construction - Finally, after all this time. The website is receiving a major update. Which includes a new host. And better aesthetics.
The changes will allow me to finally start adding holidays and important days according to a number of criteria. But, first, I am actually trying to work on some styling. This website did not even have a set font.
In the mean time, you can check Wikipedia: International Fixed Date Calendar for more information.