That's a great question! You can watch Christmas Vacation by renting the movie from your local library or video rental store, or you can purchase a copy online. You can also stream the movie online through services like Netflix or Hulu. Additionally, you can watch the movie on cable or satellite TV, if you have a subscription that includes it. Whichever method you choose, just make sure you have some popcorn and hot chocolate ready to enjoy while you watch!