Super-Computus Easter calculator!

computus.cs

    using System;
    using System.Linq;
    using System.Net;
    using System.Text.RegularExpressions;

    namespace Computus
    {
        class Program
        {
            static Regex NodePattern = new Regex(@"<pre>.*?</pre>", RegexOptions.IgnoreCase|RegexOptions.Singleline);
            static Regex DatePattern = new Regex(@"(\d+)(st|nd|rd|th) (April|March) (\d\d\d\d)", RegexOptions.IgnoreCase|RegexOptions.Singleline);

            static void Main(string[] args)
            {
                using (var client = new WebClient())
                {
                    var data = client.DownloadString("http://tlarsen2.tripod.com/anthonypolumbo/apeasterdates.html");
                    var dates = NodePattern.Matches(data).Cast<Match>().Select(match => match.Value)
                        .SelectMany(section => DatePattern.Matches(section).Cast<Match>().Select(match => match.Value
                            .Replace("st", String.Empty)
                            .Replace("nd", String.Empty)
                            .Replace("rd", String.Empty)
                            .Replace("th", String.Empty)))
                        .Select(date => DateTime.ParseExact(
                            date,
                            new[] { "dd MMMM yyyy", "d MMMM yyyy" },
                            System.Globalization.CultureInfo.InvariantCulture,
                            System.Globalization.DateTimeStyles.AdjustToUniversal))
                        .Where(date => date.Year > 2014 && date.Year < 2026)
                        .OrderBy(date => date);

                    foreach (var date in dates)
                    {
                        Console.WriteLine(date.ToShortDateString());
                    }
                }
            }
        }
    }