Promote your business to the callers while they're on hold. Inform them of your range of products and services, their benefits and how they can help them. Or just re-enforce your branding with some pleasant background music.
Length – if your callers typically wait 2 minutes at a time, then at least 2 minutes of programming should be the goal. The idea is to ensure the callers don’t hear repeated messages every time they call. A typical on-hold message is 4-8 minutes in length.

"We have had great feedback from customers. When we [pick up the phone] they are laughing and in the best mood. They say the messages are hilarious. That was my whole plan - to make being on hold enjoyable." - Rachelle Dicker / Gold Rush Express
Here are a few things to keep in mind to have a killer script your callers will be receptive to: Speak to your audience: When creating a script, make sure you know WHO you’re talking to above anything else. Is it moms, teenagers or middle-aged men who like golf? Appeal to their interests in relation to your business with a captive voice, and they’ll be much more willing to listen (and be patient while doing so). Time it appropriately: You know your business better than anyone else, so as such, you’re probably aware of a caller’s average hold times. While this can vary with growth and other factors, make sure you record enough messages to fill the time so a caller isn’t stuck hearing an eternal loop of the same 3 messages. They’ll thank you for it by being far less irritated. Stay current: Some companies have seasonal sales and changes, so including this in your script as the year progresses means you remain relevant with the latest and greatest. For example, during the holidays you can say “Seasons greetings from Fletcher’s Flowers...” or something similar. You can also include event notifications, advertisements, and other informational messages so they learn more about your business. Be natural: Think about how you’d like to be talked to. Typically, a robot isn’t the first thing that comes to mind. Writing for auditory purposes elicits a different approach than writing for digital or print. Make sure whatever your script is that you read it aloud, and test it out on coworkers or friends. If they get bored or disengage, chances are, your callers will too. Know their path: What’s your end goal for what you’d like your caller to accomplish? Tailor your messaging to them based on what you come up with. If you’d like to upsell, consider using some on hold time to discuss a company-wide promotion they can take advantage of, or a fun fact about your industry they wouldn’t know. Give a call-back option: If your phone system has the feature and a caller doesn’t have time to spend on hold, offer them the option to receive a callback without affecting their position in line, or to leave a message. This can alleviate the stress of waiting.