As of Monday evening, YouTube's website has been replaced by the following page:
Where are these "highly trained monkeys" coming from? It's unclear. IsItDown.com estimates the service disruption started within the past two hours or so.
While the homepage appears to be down, you can still watch YouTube videos you find elsewhere -- like this one of puppies.
We'll update you with more information as it's released.
UPDATE 6:03 PM ET: Is It Down Right Now is saying that YouTube is "up and reachable."