Here is a great project that is easy to build. This perpetual calendar allows you to easily see the day, month and date and the best part is it can be built using wood from your scrap pile. Follow along at the link to see how to build it.
Build a slide-rule calendar for your desk using the free woodworking tutorial at the link. So handsome.
Build this compact endless calendar using these free instructions. There is also an explanation of how it works.
This wood block calendar is easy to build using this free tutorial. It is coated with clear chalkboard paint.