using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public class thing{

        public string Name {get; set;}

        public int Id {get; set;}

        public DateTime When {get; set;}

        public thing(string name, int id, DateTime when){

            Name = name;

            Id = id;

            When = when;

        }

    }

    public static void Main()

    {

        var things = new List<thing>();

        things.Add(new thing("one",1,DateTime.Now.AddDays(1)));

        things.Add(new thing("one",1,DateTime.Now.AddDays(2)));

        things.Add(new thing("two",2,DateTime.Now.AddDays(1)));

        var grouped = (from t in things

                       group t by new {t.Id, t.Name} into g

            select g).ToList();

        grouped.ForEach(g => Console.WriteLine(string.Format("{0} ({1}) : {2}", g.Key.Id, g.Key.Name, g.Max(t => t.When))));

    }

}