Adding Event Categories to the "Family Calendar" Template

EricHammons Yes, you can. To expand the list of categories is easy. Change the named range "Event_Categories", currently pointing to the list 5 categories in H5:H20. So, if you want to work with 10 categories, set this named range to H5:H25, using the Name Manager on the Formulas ribbon and copy the format of cell H20 down to H25 (to make it look good). Now you can choose from these 10 categories in column E on the first sheet.

But, this particular template comes with one big flaw. The monthly sheets are linked to the event list by VLOOKUP. This function can only pick-up the first event for any given day. You can enter multiple events for the same day, but the calendar will only show the first one from the list. That renders the template completely useless, in my opinion. You'd need to rewrite this formula and use modern functions like TEXTJOIN and FILTER to overcome this serious lack of functionality.

And then there are a great number of conditional formatting rules that set the color of each day number in the monthly sheets based on the type of the first (!) event listed that day.  So, you'll have pick some colors first and add rules for each of the added categories, on each of the monthly sheets.

All of this support my own opinion that these standard templates are not meant to be tinkered with. Use them as they are or not use them at all.