var publicHolidays = DateSystem.GetPublicHoliday(2017, "DE");
foreach (var publicHoliday in publicHolidays)
{
    //publicHoliday...
    //publicHoliday.Date -> The date
    //publicHoliday.LocalName -> The local name
    //publicHoliday.Name -> The english name
    //publicHoliday.Fixed -> Is this public holiday every year on the same date
    //publicHoliday.Global -> Is this public holiday in every county (federal state)
    //publicHoliday.Counties -> Is the public holiday only valid for a special county ISO-3166-2 - Federal states
    //publicHoliday.Type -> Public, Bank, School, Authorities, Optional, Observance
}

var startDate = new DateTime(2016, 5, 1);
var endDate = new DateTime(2018, 5, 31);
var publicHolidays = DateSystem.GetPublicHoliday(startDate, endDate, CountryCode.DE);
foreach (var publicHoliday in publicHolidays)
{
	//publicHoliday...
}

var date = new DateTime(2017, 1, 1);
if (DateSystem.IsPublicHoliday(date, CountryCode.DE))
{
    Console.WriteLine("Is public holiday");
}

var date = new DateTime(2017, 1, 1);
if (DateSystem.IsWeekend(date, CountryCode.DE))
{
    Console.WriteLine("Is weekend");
}

var date = new DateTime(1900, 1, 1);
var age = DateSystem.GetAge(date);