If you think knock-knock jokes are corny, imagine what your customers will think if you try to use this low form of humor to upsell them. But don’t knock it until you’ve tried it. According to restaurant marketing expert Tom Feltenstein, author of 501 Killer Marketing Tactics to Increase Sales, Maximize Profits and Stomp Your Competition, it can boost your bottom line, especially when you build a staff incentive program around it.

When sales are suffering, laughter can be the best medicine. In 501 Killer Marketing Tactics, Feltenstein prescribes playing a game of Knock-Knock to increase sales of selected menu items. “This is a simple icebreaker,” he writes, “and, although your staff may initially feel a little foolish, you’ll be surprised how well it works.”

To get started, every server should wear a button that says, “Knock-Knock” and learn a few jokes associated with menu items, such as wings, breadsticks, garlic knots, desserts and other add-ons. The server approaches the table and gets the conversation started with an offer to play the Knock-Knock game.

Knock-knock. Who’s there? Wanda. Wanda who? Wanda get started with an order of our delicious buffalo ranch chicken wings?

Knock-knock. Who’s there? Dewey. Dewey who? Dewey care to order an appetizer?

Knock-knock. Who’s there? Annie. Annie who? Anniebody in the mood for dessert?

Run the promotion for four weeks, Feltenstein advises. As you go along, use a tally board to track each server’s item sales every day. At the end of each week, the employee with the highest sales wins a cash bonus or some other substantial reward. At the end of the four-week period, an additional reward is offered for the grand prize winner. If you offer cash bonuses, just make sure you set a minimum sales requirement to cover the cost of your rewards.