gui button vary font size

GUI makes it easy to change font color or the background image of a button on an Active button. I'm not a GUI expert, but the only way I could see to get the behavior you describe is a bit involved. I use a GUISyle copies from GUI.ski.button, and vary the font size.

 #pragma strict
 
 private var rect : Rect = new Rect(100,100,200,50);
 private var gs : GUIStyle = null;
 
 private var normalSize = 13;
 private var smallSize = 8;
 
 function OnGUI() {
     var e : Event = Event.current;
     
     if (gs == null) { 
         gs = new GUIStyle(GUI.skin.button);
         gs.fontSize = normalSize;
     }
     
     if (rect.Contains(e.mousePosition) && (e.type == EventType.MouseDown)) {
         Invoke("SmallSize", 0.1);
     }
     
     if (e.type == EventType.MouseUp) {
         gs.fontSize = normalSize;
         CancelInvoke("SmallSize");
     }
     
     GUI.Button(rect, "Some text", gs);
 }
 
 function SmallSize() { 
     gs.fontSize = smallSize;
 }