I would like to be able to create event categories within people and event calendars so that when I log an event, I can select it and it can be a different color, making it easier to scan the calendar, focused on specific types of events.

For example, PTO vs Out of Office are different types of events and have different implications. Typically, PTO means the individual is not available; whereas out of office or travel indicates that the individual is working but may not be available at times throughout the day and you need to communicate with them in specific modes (e.g. text or call vs email). Same thing - it's helpful to indicate that I am on demo or sales call during a specific time..again, not necessarily available at that time, but am during the day.