function OnCollisionStay(collision : Collision) {
    // Check if the collider we hit has a rigidbody
    // Then apply the force
    for (var contact : ContactPoint in collision.contacts) {
        print(contact.thisCollider.name + " hit " + contact.otherCollider.name);
        // Visualize the contact point
        Debug.DrawRay(contact.point, contact.normal, Color.white);
    }
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OnCollisionStay(Collision collision) {
        foreach (ContactPoint contact in collision.contacts) {
            print(contact.thisCollider.name + " hit " + contact.otherCollider.name);
            Debug.DrawRay(contact.point, contact.normal, Color.white);
        }
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OnCollisionStay(collision as Collision):
        for contact as ContactPoint in collision.contacts:
            print(((contact.thisCollider.name + ' hit ') + contact.otherCollider.name))
            Debug.DrawRay(contact.point, contact.normal, Color.white)

// A grenade
// - instantiates a explosion prefab when hitting a surface
// - then destroys itself

var explosionPrefab : Transform;

function OnCollisionEnter(collision : Collision) {
    // Rotate the object so that the y-axis faces along the normal of the surface
    var contact = collision.contacts[0];
    var rot = Quaternion.FromToRotation(Vector3.up, contact.normal);
    var pos = contact.point;
    Instantiate(explosionPrefab, pos, rot);
    // Destroy the projectile
    Destroy (gameObject);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Transform explosionPrefab;
    void OnCollisionEnter(Collision collision) {
        ContactPoint contact = collision.contacts[0];
        Quaternion rot = Quaternion.FromToRotation(Vector3.up, contact.normal);
        Vector3 pos = contact.point;
        Instantiate(explosionPrefab, pos, rot) as Transform;
        Destroy(gameObject);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public explosionPrefab as Transform

    def OnCollisionEnter(collision as Collision):
        contact as ContactPoint = collision.contacts[0]
        rot as Quaternion = Quaternion.FromToRotation(Vector3.up, contact.normal)
        pos as Vector3 = contact.point
        (Instantiate(explosionPrefab, pos, rot) as Transform)
        Destroy(gameObject)