• Unity3D

• MonoDevelop (comes with Unity3D)

You don't NEED visual studio. If you really prefer its intellisense, then grab Visual Studio Express C# 2008 as I think only that one runs without much fuss.

Here is an example of a Hello World script(must be attached to scene object) through debug.log in c#. You will see hello world in the console window or in the lower left hand corner of the unity window.

using UnityEngine;

using System.Collections;

public class HelloWorldScript : MonoBehaviour
{

    // Use this for initialization
    void Start()
    {
        Debug.Log("Hello World");
    }

    // Update is called once per frame
    void Update()
    {

    }
}