var sliderValue : float = 1.0;

function OnGUI() {
// Wrap everything in the designated GUI Area
GUILayout.BeginArea (Rect (0,0,200,60));
// Begin the singular Horizontal Group
GUILayout.BeginHorizontal();
// Place a Button normally
GUILayout.RepeatButton ("A button with\ntwo lines");
// Place a space between the button and the vertical area
// so it fits the whole area
GUILayout.FlexibleSpace();
// Arrange two more Controls vertically beside the Button
GUILayout.BeginVertical();
GUILayout.Box("Value:" + Mathf.Round(sliderValue));
sliderValue = GUILayout.HorizontalSlider (sliderValue, 0.0, 10);

// End the Groups and Area
GUILayout.EndVertical();
GUILayout.EndHorizontal();
GUILayout.EndArea();
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public float sliderValue = 1.0F;
void OnGUI() {
GUILayout.BeginArea(new Rect(0, 0, 200, 60));
GUILayout.BeginHorizontal();
GUILayout.RepeatButton("A button with\ntwo lines");
GUILayout.FlexibleSpace();
GUILayout.BeginVertical();
GUILayout.Box("Value:" + Mathf.Round(sliderValue));
sliderValue = GUILayout.HorizontalSlider(sliderValue, 0.0F, 10);
GUILayout.EndVertical();
GUILayout.EndHorizontal();
GUILayout.EndArea();
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public sliderValue as single = 1.0F

def OnGUI():
GUILayout.BeginArea(Rect(0, 0, 200, 60))
GUILayout.BeginHorizontal()
GUILayout.RepeatButton('A button with\ntwo lines')
GUILayout.FlexibleSpace()
GUILayout.BeginVertical()
GUILayout.Box(('Value:' + Mathf.Round(sliderValue)))
sliderValue = GUILayout.HorizontalSlider(sliderValue, 0.0F, 10)
GUILayout.EndVertical()
GUILayout.EndHorizontal()
GUILayout.EndArea()