A Library to provide Undo functionality, with depth and size limits. All core features implemented, see example in test project. Basic Usage:

List<string> ourList = new List<string>(new string[] { "plastics", "hardware", "housewares", "toys" });
Undo<List<string>> history = new Undo<List<string>>();
history.AddItem(new List<string>(ourList.ToArray()));
ourList.Add("books");
history.AddItem(new List<string>(ourList));
ourList.Add("furniture");
history.AddItem(new List<string>(ourList));
ourList.Add("auto parts");
history.AddItem(new List<string>(ourList));
string currentSize = history.GetSize().ToString();
Console.WriteLine("Current Size: {0}", currentSize);
for (int i = 0; i < 15; i++)
        {
            history.Up();
            current = history.Current.Value;
            Console.WriteLine("Printing Item {0}: Time: {1} Date: {2};", history.Cursor.ToString(), history.Current.Time, history.Current.Date);
            foreach (var item in current)
            {
                Console.Write(item + ",");
            }
            Console.WriteLine();

            Console.WriteLine("Moving Up:");
            Console.WriteLine();



        }
Console.ReadKey(false);

See Example Project for more in depth usage. Bugs/Features please post in issues.