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))