Just a sample site of a possible usage of DateTimeExtensions nuget package.
January 01 New Year
March 26 Easter Monday
May 01 International Workers' day
May 03 Feast of the Ascension
May 08 Victory in Europe Day
May 14 Pentecost Monday
July 14 Bastille Day
August 15 Assumption
November 01 All Saints
November 11 Veterans Day
December 25 Christmas
DateTimeExtensions DateTimeExtensions