Enabled Colliders will collide with other colliders, disabled Colliders won't.

This is shown as the small checkbox in the inspector of the Colliders.

	collider.enabled = false;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        collider.enabled = false;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		collider.enabled = false