Task: Holidays related to Easter
C#: using System;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;

internal class Program
{
    private static readonly OrderedDictionary _holidayOffsets = new OrderedDictionary
                                                                    {
                                                                        {"Easter", 0},
                                                                        {"Ascension", 39},
                                                                        {"Pentecost", 49},
                                                                        {"Trinity", 56},
                                                                        {"Corpus", 60},
                                                                    };

    static void Main(string[] args)
    {
        Console.WriteLine("Christian holidays, related to Easter, for each centennial from 400 to 2100 CE:");
        for (int year = 400; year <= 2100; year += 100)
            OutputHolidays(year);

        Console.WriteLine();
        Console.WriteLine("Christian holidays, related to Easter, for years from 2010 to 2020 CE:");
        for (int year = 2010; year <= 2020; year += 1)
            OutputHolidays(year);
    }

    static void OutputHolidays(int year)
    {
        var easter = CalculateEaster(year);
        var holidays = from kp in _holidayOffsets.OfType<DictionaryEntry>()
                       let holiday = easter.AddDays(Convert.ToInt32(kp.Value))
                       select kp.Key + ": " + string.Format("{0,2:ddd} {0,2:%d} {0:MMM}", holiday);
        Console.WriteLine("{0,4} {1}", year, string.Join(", ", holidays.ToArray()));
    }

    static DateTime CalculateEaster(int year)
    {
        var a = year % 19;
        var b = year / 100;
        var c = year %100;
        var d = b / 4;
        var e = b % 4;
        var f = (b + 8) / 25;
        var g = (b - f + 1) / 3;
        var h = (19 * a + b - d - g + 15) % 30;
        var i = c / 4;
        var k = c % 4;
        var l = (32 + 2 * e + 2 * i - h - k) % 7;
        var m = (a + 11 * h + 22 * l) / 451;
        var numerator = h + l - 7 * m + 114;
        var month = numerator / 31;
        var day = (numerator % 31) + 1;
        return new DateTime(year, month, day);
    }
}

Python: from dateutil.easter import *
import datetime, calendar

class Holiday(object):
    def __init__(self, date, offset=0):
        self.holiday = date + datetime.timedelta(days=offset)

    def __str__(self):
        dayofweek = calendar.day_name[self.holiday.weekday()][0:3]
        month = calendar.month_name[self.holiday.month][0:3]
        return '{0} {1:2d} {2}'.format(dayofweek, self.holiday.day, month)

def get_holiday_values(year):
    holidays = {'year': year}
    easterDate = easter(year)
    holidays['easter'] = Holiday(easterDate) 
    holidays['ascension'] = Holiday(easterDate, 39)
    holidays['pentecost'] = Holiday(easterDate, 49)
    holidays['trinity'] = Holiday(easterDate, 56)
    holidays['corpus'] = Holiday(easterDate, 60)
    return holidays
    
def print_holidays(holidays):
    print '{year:4d} Easter: {easter}, Ascension: {ascension}, Pentecost: {pentecost}, Trinity: {trinity}, Corpus: {corpus}'.format(**holidays)
    
if __name__ == "__main__":
    print "Christian holidays, related to Easter, for each centennial from 400 to 2100 CE:"
    for year in range(400, 2200, 100):
        print_holidays(get_holiday_values(year))

    print ''
    print "Christian holidays, related to Easter, for years from 2010 to 2020 CE:"
    for year in range(2010, 2021):
        print_holidays(get_holiday_values(year))