Just a sample site of a possible usage of DateTimeExtensions nuget package.
January 01 New Year
April 10 Easter Monday
May 01 International Workers' day
May 08 Victory in Europe Day
May 18 Feast of the Ascension
May 29 Pentecost Monday
July 14 Bastille Day
August 15 Assumption
November 01 All Saints
November 11 Veterans Day
December 25 Christmas
DateTimeExtensions DateTimeExtensions