I just received (from R. for xmas) and am looking forward to reading Craig Child’s Apocalyptic Planet: Field Guide to the Everending Earth, which I imagine will fit nicely w/ this Wikipedia entry on the far future. The number of catastrophic things that have happened and will happen to the earth really dwarfs most anthropic notions of time, disaster, and crisis.

And on the other side of this spectrum, check out The Long Now Foundation.