I have a post up on using calendar tables:
There’s one problem with picking a SQL Saturday in April: Easter and Passover tend to run right around that time, and nobody wants a SQL Saturday on Passover or the day before Easter. Unfortunately, our calendar table doesn’t include holiday information. So let’s add it!
Working with holidays and working with fiscal years versus calendar years are just two of the uses of calendar tables. But they’re the only two that I show.