using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

     Dictionary<string, List<string>> dictionary =  new Dictionary<string, List<string>>();

     dictionary.Add("MIESTAS", new List<string>() {"test", "test1", "test2", "test3", "test4", "test5", "test6"});  

     Random _random = new Random();

     var size = dictionary.Values.ElementAt(0).Count - 1;

     Console.WriteLine("Tema: " + dictionary.Keys.ElementAt(0));

     Console.WriteLine("Zodziai: " + dictionary.Values.ElementAt(0).ElementAt(_random.Next(0, size)));

    }

}

​