// Activate the gravity of other object we touch
function OnControllerColliderHit(hit : ControllerColliderHit) {
if(hit != null) {
hit.rigidbody.useGravity = true;
}
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void OnControllerColliderHit(ControllerColliderHit hit) {
if (hit != null)
hit.rigidbody.useGravity = true;

}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def OnControllerColliderHit(hit as ControllerColliderHit):
if hit != null:
hit.rigidbody.useGravity = true