When you absolutely, positively have to be a smug asshole to your friends and love ones one last time, there's:
In a nutshell, the site queues up messages from you to your infidel friends that will be dispatched after the Rapture. And how does the site know that the Rapture has happened? Because at least three of the site's five designated holier-than-thou's will have failed to log in for three days running.
This begs the question of what would happen should, God forfend, a catastrophic but non-Rapture event should wipe out those saintly designees all at once. Can you imagine the chaos that would ensue should all those ha-ha-I'm-in-Heaven-now messages get sent while their authors are still miserably earthbound? I hope someone hacks the site and makes it happen.
Of course, maybe the opposite will happen, if Jesus frowns on seeing people profiting from the anticipation of the Rapture. In that case, maybe none of the designees will get lifted up, up, and away on that great and fateful day.