Made famous by George Costanza as you can see the clip here, the answering machine song may seem like a good idea. It's out of the box, unexpected, and definitely a novelty, but unless you're in the music business, it's probably not a good idea. You'll definitely irritate your mother (or anyone else important who calls you frequently) and you won't make a good first impression with your message.
When your small business is closed, ensure that your callers know that! If appropriate, you might want to reiterate your business hours to manage callback expectations.

Creating a professional voicemail greeting isn’t complicated, but you need to keep a few things in mind to ensure success. The following tips will help: Be friendly and welcoming - let your company's personality shine!; Have a clear voice, speak at a slow to moderate pace, minimize background noise; Ensure the greeting is human and approachable; Keep the greeting short and informative; Ensure the greeting doesn’t sound robotic or unnatural; Show your gratitude for the call by saying thank you; Manage expectations by clearly stating when the client can expect a callback.
The first time you log in to your new Boston University Voicemail, you will be prompted to change your pin. New pins must be a minimum of six digits and can not contain common or repeating sequences of numbers.