The Secret is a great way to award multiple prizes to listeners (movie tickets, etc). The premise is quite simple, but most of the audience will never figure it out. That means you can bring it back on a regular basis.
You have The Secret. If a caller discovers it, they win a prize. The incentive doesn’t have to be large. It’s a good way to hand out large inventory prizes like movie tickets or lunch coupons.
Some will win by accident, meaning there will be prizes awarded, so don’t worry about never having a winner. But this game is about the fun of play along, not the incentive.