FizzBuzz kata in C# using LINQ and a helper class to how the translation rules.

fizzbuzz_aggregate.cs

using System;
using System.Collections.Generic;
using System.Linq;
 
namespace FizzBuzz
{
    public class FizzBuzzer
    {
        public string Translate(int value)
        {
            var result = new List<Translator>
                {
                    new Translator(() => value%3 == 0, "Fizz"),
                    new Translator(() => value%5 == 0, "Buzz")
                }.Aggregate(string.Empty, (s, t) => s += t.Translate());
 
            return string.IsNullOrEmpty(result) ? value.ToString() : result;
        }
 
        class Translator
        {
            Func<bool> Test { get; set; }
            string Translation { get; set; }
 
            public Translator(Func<bool> test, string translation)
            {
                Test = test;
                Translation = translation;
            }
 
            public string Translate()
            {
                return Test() ? Translation : string.Empty;
            }
        }
    }
}

See also my blog post which goes with this gist.
http://comp-phil.blogspot.com/2014/05/the-form-of-katas.html