Sometimes you know when a surprise party is being planned, especially if you are prone to sleuthing. The trick is to plan a surprise within a surprise.
My husband gathered dozens of pictures of me through the years and had them blown up and mounted on foam core. He decorated all the walls of our house with these (sometimes embarrassing) pictures for a surprise that I will never forget. And I’m sure my friends are never going to let me forget the picture of my brother and me shaking Ronald Reagan’s hand.