function OnGUI() {
Debug.Log("Current detected event: " + Event.current);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void OnGUI() {
Debug.Log("Current detected event: " + Event.current);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def OnGUI():
Debug.Log(('Current detected event: ' + Event.current))