LINQанем анаграммы.

Задача (подсмотренно у Брэда Фитзпатрика)

Last night at Beau's party, one of Beau's guests mentioned he's expecting twins shortly, which is why is wife wasn't at the party.

I drunkenly suggested he name his kids two names that were anagrams of each other. I then wandered off downstairs to find such suitable names.

ЛИНКану решение:

   var pairs = from pair in
     from name in
     from name in File.ReadAllLines("d:\\dist.male.first") select name.Split(' ')[0]
     group name by name.Sort()
     where pair.Count() > 1
     select pair;

   foreach (var pair in pairs)
      Console.WriteLine(String.Join(",", pair.ToArray()));

К сожалению в .NET Framework нет встроенной функции сортировки строки...
Поэтому полный вариант выглядит не так красиво. Опять же обрамление из using...

using System;
using System.IO;
using System.Linq;

namespace anagram
{
    static class Program
    {
        public static string Sort(this string s)
        {
            char[] arr = s.ToArray();
            Array.Sort(arr);
            return new string(arr);
        }

        static void Main(string[] args)
        {
            var pairs = from pair in
                            from name in
                                from name in File.ReadAllLines("d:\\dist.male.first") select name.Split(' ')[0]
                            group name by name.Sort()
                        where pair.Count() > 1
                        select pair;

            foreach (var pair in pairs)
                Console.WriteLine(String.Join(",", pair.ToArray()));
        }
    }
}