Just a sample site of a possible usage of DateTimeExtensions nuget package.
January 01 New Year
April 03 Good Friday
April 05 Easter
April 06 Easter Monday
April 27 Kingsday
May 05 Liberation Day
May 14 Feast of the Ascension
May 24 Pentecost
May 25 Pentecost Monday
December 25 Christmas
December 26 Boxing Day
DateTimeExtensions DateTimeExtensions