The official website for a transhumanist-themed RPG which is light on the rules but heavy on the "Wow, my character can do that?!" factor.
An interesting article discussing a hierarchy of potential eschatological events.
A well thought out and carefully written paper discussing existential risks to the human race.
A website that discusses apocalypse/X-threat scenarios with a tongue-in-cheek sense of humor.
Anders Sandberg's transhuman warning signs.