Whether you’re out for the day or are off for the week, the first rule of an out of office voicemail greeting is: let callers know when you’ll be back! You’ll save them the frustration of continuing to call and yourself the hassle of listening to redundant voicemails. It’s also a good idea to set the expectation of whether you are answering messages while you’re away, and who they can reach for assistance in your absence.
A clever, witty voicemail message can be short or long, complex or simple, as long as it is entertaining. Using famous lines from TV shows or movies is a great place to start. There is a lot of creative wordplay that you can use based on famous lines from classics like The Twilight Zone. For instance, you could say, "Hello, you've reached the Twilight Phone, where every message is sent into another dimension. To receive an interdimensional call, just leave your name and number, and I'll call you from the closest parallel universe."

Any message you leave will be broadcast into the future…. A is for academics, B is for beer. So leave a message.
Voicemails don’t necessarily have to be monotonous or extremely jazzy or funky. What you should be looking for is a balance between the two. Whenever you call someone and their voicemail greeting is playing, it tells you a lot about who they are, as a person. Which is why, you’ve got to put a little bit of “you” when it comes to voicemail. And the best part about all of this is, since you couldn’t come to the phone, at least the callers are having a good time listening to the message.