// print the transform's name that collided with this transform
function OnControllerColliderHit(hit : ControllerColliderHit) {
     Debug.Log("I'm colliding with: " + hit.transform.name);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OnControllerColliderHit(ControllerColliderHit hit) {
        Debug.Log("I'm colliding with: " + hit.transform.name);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OnControllerColliderHit(hit as ControllerColliderHit):
        Debug.Log(('I\'m colliding with: ' + hit.transform.name))