It would be great to see the ability to create a holiday schedule.
This type of schedule should allow a year based date selection. Including the 4th Thursday of November and also January 1st.
This type of schedule should be able to be used to modify other existing schedules. By this I mean for the 'Weekdays' schedule you would have the option to include, or exclude a holiday schedule.
If it was allowed to have multiple holiday schedules then it could be used for both business closed days, but also to allow a user to select a schedule for their vacation days.