Just a sample site of a possible usage of DateTimeExtensions nuget package.
January 01 Ano Novo
March 05 Carnaval
April 19 Sexta-feira Santa
April 21 Pascoa
May 01 Dia do Trabalhador
June 20 Corpo de Cristo
September 07 Dia da Independência
October 12 Nossa Srª da Aparecida
November 02 Dia de Finados
November 15 Dia da Republica
December 25 Natal
DateTimeExtensions DateTimeExtensions