The first collider in contact.

	// Prints the name of this collider
	function OnCollisionEnter(other : Collision) { 
	 	print("This collider is named: " + other.contacts[0].thisCollider.name);
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnCollisionEnter(Collision other) {
        print("This collider is named: " + other.contacts[0].thisCollider.name);
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnCollisionEnter(other as Collision) as void:
		print(('This collider is named: ' + other.contacts[0].thisCollider.name))