Billiard games date back as far as the 15th century, even being mentioned in the works of Shakespeare. With such a long history it's amazing no one thought to pick up the 8-ball and ask it questions until 1946.
Bring a fresh 9v battery with you if you if you want this 8-ball to spill it's secrets, and be gentle, a flip of the wrist when it prompts you to ask a question is all it takes to generate a reply, vigorus shaking is not needed. Be warned, she is very stubborn and it may take a lof of questions before she'll give you the code you seek. She may even give you the answer you want in the wrong order, so pay attention to the wording!