class Program
    {
        static readonly BlockQueue<int> Queue = new BlockQueue<int>();
        static void Process(object taskName)
        {
            while (true)
            {
                try
                {
                    var item = Queue.Dequeue();

                    Console.WriteLine("{0}: процесс {1}.", taskName, item);
                    Thread.Sleep(100);
                }
                catch (InvalidOperationException)
                {
                    Console.WriteLine("{0} завершён", taskName);
                    return;
                }

            }
        }
        static void Main()
        {
            var tasks = new Task[5];

            for (var i = 0; i < tasks.Length; i++)
            {
                var num = i + 1;
                tasks[i] = Task.Factory.StartNew(() => Process("Поток" + num));
            }
            for (var i = 0; i < 50; i++)
                Queue.Enqueue(i);

            Task.WaitAll(tasks);
            Console.WriteLine("Все потоки закончили работу");
            Console.ReadLine();
        }
    }

amespace ConsoleApplication1
{
    class Product<T>
    {
        readonly T _obj;

        public Product(T obj)
        {
            _obj = obj;
        }

        public T Value { get { return _obj; } }
    }
}

using System.Collections.Generic;

namespace ConsoleApplication1
{
    internal class BlockQueue<T>
    {
        private readonly Queue<Product<T>> _queue;

        public BlockQueue()
        {
            _queue = new Queue<Product<T>>();
        }

        public void Enqueue(T obj)
        {
            lock (_queue)
            {
                _queue.Enqueue(new Product<T>(obj));
            }
        }

        public T Dequeue()
        {
            lock (_queue)
            {
                return _queue.Dequeue().Value;
            }
        }
    }
}