The Pleasure Saucers (also known as Escape Vessels) will come on X-Day and Rupture all dues-paying SubGenii. Then they can have sex with Alien Sex Goddesses (or alien sex gods; they can be whatever you want them to be.)
According to some reports, this sexual activity will happen the whole time on the journey back to Planet X.
The Holocaustals claim the X-ists will then destroy the planet Earth and its humans with their giant lasers. The Ivengelicals, on the other hand, claim the Earth will not be destroyed and its humans will not be killed, but will instead be enslaved.
Either way, anyone who's not a Nar (fool) will want to be on one. This can be accomplished by joining the Church of the SubGenius.