using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    private static readonly Random _r = new Random();

    private static IEnumerable<(T, T)> FunkyLotto<T>(IEnumerable<T> source)

    {

        var pool = source.ToList();

        var iteration = pool.ToList();

        foreach (var item in iteration)

        {

            int choice;

            if (pool.Count == 2 && pool.IndexOf(item) >= 0) // special case when there is only 2 left, and there is a case for a duplicate

                choice = (pool.IndexOf(item) + 1) % pool.Count;

            else

                choice = _r.Next(0, pool.Count);

            choice = Equals(item, pool[choice]) ? (choice + 1) % pool.Count : choice;

            yield return (item, pool[choice]);

            pool.RemoveAt(choice);

        }

    }

​

    public static void Main()

    {

        var list = new[]{"Joe", "John", "Chris", "Henry", "Tom", "Patrick"};

        foreach (var result in FunkyLotto(list))

            Console.WriteLine(result);

    }

}