A friend of mine recently referred me to the Post-Rapture Post, a service that offers to deliver a message to your unsaved relatives when the Rapture comes and you are no longer available to point them toward Christ. It offers a wide range of messages, from personalized notes to simple premade cards that say "I told you so." It offers various Cafe Press sort of merchandise, and even a guide on how to navigate the difficulties of life now that the Great Tribulation has begun (an authentic Bible).
The site is absolutely stunning in the respectful way it goes about its business so quietly tongue-in-cheek. There are appropriate Scripture verses on every page, and down-to-earth explanations of basic Christian doctrine pertaining to salvation.
From the Post-Rapture Post's promotional material:
Just write your letter and it will be hand-delivered immediately following the exodus of the pure from the Earth. But you must be thinking to yourself, "How can the letters be delivered after the Rapture?" The answer is simple. The creators of this site are Atheists. That's right, we don't believe in God. How else would we be able to deliver your correspondence after the Rapture?"
I don't believe in the Rapture myself, so I suppose if I were to use the Rapture Post, my message might say something like, "Well, it looks my eschatology was wrong, but at least my theology was better than yours. Neener neener."
Be sure to check out their testimonials page.