// Scale a button by 1.5 times each time is pressed.

private var scale : Vector2 = Vector2(1,1);
private var pivotPoint : Vector2;

function OnGUI () {
pivotPoint = Vector2(Screen.width/2,Screen.height/2);
GUIUtility.ScaleAroundPivot (scale, pivotPoint);
if(GUI.Button(Rect(Screen.width/2-25, Screen.height/2-25, 50, 50),"Big!")){
scale += Vector2(0.5,0.5);
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
private Vector2 scale = new Vector2(1, 1);
private Vector2 pivotPoint;
void OnGUI() {
pivotPoint = new Vector2(Screen.width / 2, Screen.height / 2);
GUIUtility.ScaleAroundPivot(scale, pivotPoint);
if (GUI.Button(new Rect(Screen.width / 2 - 25, Screen.height / 2 - 25, 50, 50), "Big!"))
scale += new Vector2(0.5F, 0.5F);

}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

private scale as Vector2 = Vector2(1, 1)

private pivotPoint as Vector2

def OnGUI():
pivotPoint = Vector2((Screen.width / 2), (Screen.height / 2))
GUIUtility.ScaleAroundPivot(scale, pivotPoint)
if GUI.Button(Rect(((Screen.width / 2) - 25), ((Screen.height / 2) - 25), 50, 50), 'Big!'):
scale += Vector2(0.5F, 0.5F)