Scripting Reference
MonoBehaviour.CancelInvoke

function CancelInvoke () : void

Description

Cancels all Invoke calls on this MonoBehaviour.

JavaScript 
// Starting in 2 seconds.
// a projectile will be launched every 0.3 seconds
var projectile : Rigidbody;
InvokeRepeating("LaunchProjectile", 2, 0.3);

// Cancels the repeating invoke call, 
// when the user pressed the ctrl button
function Update() {
    if (Input.GetButton ("Fire1"))
        CancelInvoke();
}

function LaunchProjectile () {
    instance = Instantiate(projectile);
    instance.velocity = Random.insideUnitSphere * 5;
}
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Rigidbody projectile;
    void Update() {
        if (Input.GetButton("Fire1"))
            CancelInvoke();
        
    }
    void LaunchProjectile() {
        instance = Instantiate(projectile);
        instance.velocity = Random.insideUnitSphere * 5;
    }
    void Example() {
        InvokeRepeating("LaunchProjectile", 2, 0.3F);
    }
}
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public projectile as Rigidbody

    def Update():
        if Input.GetButton('Fire1'):
            CancelInvoke()

    def LaunchProjectile():
        instance = Instantiate(projectile)
        instance.velocity = (Random.insideUnitSphere * 5)

    def Example():
        InvokeRepeating('LaunchProjectile', 2, 0.3F)

function CancelInvoke (methodName : String) : void

Description

Cancels all Invoke calls with name methodName on this behaviour.

JavaScript 
// Starting in 2 seconds.
// a projectile will be launched every 0.3 seconds

var projectile : Rigidbody;
InvokeRepeating("LaunchProjectile", 2, 0.3);

// Cancels the repeating invoke call, 
// when the user pressed the ctrl button
function Update() {
    if (Input.GetButton ("Fire1"))
        CancelInvoke("LaunchProjectile");
}

function LaunchProjectile () {
    instance = Instantiate(projectile);
    instance.velocity = Random.insideUnitSphere * 5;
}
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Rigidbody projectile;
    void Update() {
        if (Input.GetButton("Fire1"))
            CancelInvoke("LaunchProjectile");
        
    }
    void LaunchProjectile() {
        instance = Instantiate(projectile);
        instance.velocity = Random.insideUnitSphere * 5;
    }
    void Example() {
        InvokeRepeating("LaunchProjectile", 2, 0.3F);
    }
}
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public projectile as Rigidbody

    def Update():
        if Input.GetButton('Fire1'):
            CancelInvoke('LaunchProjectile')

    def LaunchProjectile():
        instance = Instantiate(projectile)
        instance.velocity = (Random.insideUnitSphere * 5)

    def Example():
        InvokeRepeating('LaunchProjectile', 2, 0.3F)