function OnGUI () {    
        GUILayout.BeginHorizontal ("box");
        GUILayout.Button ("I'm the first button");
        GUILayout.Button ("I'm to the right");
        
        // End the horizontal group we began above
        GUILayout.EndHorizontal ();
    }

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OnGUI() {
        GUILayout.BeginHorizontal("box");
        GUILayout.Button("I'm the first button");
        GUILayout.Button("I'm to the right");
        GUILayout.EndHorizontal();
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OnGUI():
        GUILayout.BeginHorizontal('box')
        GUILayout.Button('I\'m the first button')
        GUILayout.Button('I\'m to the right')
        GUILayout.EndHorizontal()