What is the easiest way to generate quasi random numbers in C#?

Question

All I want is a pragmatic random number generator in C# so I can say e.g.

int dummyAge = MathHelpers.GetRandomNumber(20,70);

and have it seem quasi random, e.g. to generate dummy data.

Most stack overflow questions on this topic and on the web get into a philosophical discussions on true randomness which is not what I'm interested at the moment, e.g. I did one in PHP a long time ago which uses milliseconds/sleep which is fine for dummy data, I'm just trying to do this in C# quick.

Does anyone have a quick half-decent C# random number generator based on some time seed, etc. or, how could I change the following code so that it always doesn't generate the same 5 number in a row?

using System;

namespace TestRandom23874
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("the random number is: {0}", MathHelpers.GetRandomNumber(1, 10));
            Console.WriteLine("the random number is: {0}", MathHelpers.GetRandomNumber(1, 10));
            Console.WriteLine("the random number is: {0}", MathHelpers.GetRandomNumber(1, 10));
            Console.WriteLine("the random number is: {0}", MathHelpers.GetRandomNumber(1, 10));
            Console.WriteLine("the random number is: {0}", MathHelpers.GetRandomNumber(1, 10));
            Console.ReadLine();
        }
    }

    public class MathHelpers
    {
        public static int GetRandomNumber(int min, int max)
        {
            Random random = new Random();
            return random.Next(min, max);
        }
    }
}

Answer 1

public class MathHelpers
    {
        private static Random random = new Random();
        public static int GetRandomNumber(int min, int max)
        {
            return random.Next(min, max);
        }
    }

This way, you're not creating a new Random object every time, rather you're reusing the same one. When you recreate a new one quickly enough, they will yield the same results. If however, you reuse an existing one, you'll get randomness.