The Hanke-Henry Calendar

The Hanke-Henry calendar attempts to align the year so that a particular date is always on the same day of the week. It does this by slightly reducing the length of the year. Rather than a leap year adding a day every four years, it adds an entire week every five or six years in order to maintain the day alignment. Along the way, it aligns the 30/31 schedule with the quarters and makes february unexceptional.

Disk Clock currently uses a solar year – the leap weeks would still require figuring out how to change the size of disks, just like the leap days we have now.