We've created an amazing custom calendar table in Power BI that incorporates fiscal and intelligent time dimension columns. It includes easy ways to filter by rolling periods of various time dimensions as granular as day and up to year. It also includes Offset columns for Days, Weeks, Months, Quarters, and Years.

Each offset column is a numerical column that starts as 0 for the current time period (E.g. Current Day, Month, etc...). Any rows for a time period in the past is then assigned with a negative number (E.g. -1, -2, etc...), and time periods in the future are assigned a positive number (E.g. 1, 2, etc...).

This logic allows for easy filtering for relative time windows. DAX Measures can also utilize these columns for easier time intelligence calculations as well. The table also includes Parameters that allow the client to easily choose the calendar start and stop date ranges and the fiscal year start date when creating the table.