One joke involves a couple who are celebrating their 40th wedding anniversary when a fairy comes to them and says that they have been so good, and have been married so long, that they each get a wish. The wife wishes to tour the world with her husband, and airline and cruise tickets immediately appear in her hands. The man wishes for a female companion 30 years younger, and the fairy grants his wish -- he instantly becomes 90.
Another joke involves a man who is boasting to his friends that for their 40th wedding anniversary, he is taking his wife to Rome. When one of his friends asks him what he will do for their 50th, he replies, "I'll go and get her."
A third joke centers around the words of a man who, at his 40th wedding anniversary banquet, was asked to give his friends a brief speech about the benefits of being married for so long. He tells them, "I've learned that marriage is the best teacher of all. It teaches you forbearance, meekness, self-restraint, forgiveness and a great many other qualities you wouldn't have needed if you had stayed single."
Finally, there is a joke about an old man who visits a wizard to ask him to remove a curse that had been put on him exactly 40 years ago. The wizard tells him that he can only remove the curse if he knows the exact words that were used to place it on him; the old man tells him the words were, "I now pronounce you man and wife."