QUOTE
With Spore you can nurture your creature through five stages of evolution: Cell, Creature, Tribe, Civilization, and Space. Or if you prefer, spend as much time as you like making creatures, vehicles, buildings and spaceships with Spore’s unique Creator tools.
CREATE Your Universe from Microscopic to Macrocosmic - From tide pool amoebas to thriving civilizations to intergalactic starships, everything is in your hands.
EVOLVE Your Creature through Five Stages - It’s survival of the funnest as your choices reverberate through generations and ultimately decide the fate of your civilization.
EXPLORE your world and beyond - Will you rule, or will your beloved planet be blasted to smithereens by a superior alien race?
SHARE with the World - Everything you make is shared with other players and vice versa, providing tons of cool creatures to meet and new places to visit.
CREATE Your Universe from Microscopic to Macrocosmic - From tide pool amoebas to thriving civilizations to intergalactic starships, everything is in your hands.
EVOLVE Your Creature through Five Stages - It’s survival of the funnest as your choices reverberate through generations and ultimately decide the fate of your civilization.
EXPLORE your world and beyond - Will you rule, or will your beloved planet be blasted to smithereens by a superior alien race?
SHARE with the World - Everything you make is shared with other players and vice versa, providing tons of cool creatures to meet and new places to visit.
Quote from http://www.spore.com/what/platforms#PC
So basically this game lets you create and evolve your own character and eventually advance your civilization into space age technology and visit other worlds in a constantly expanding universe. Everything in the game is completely customizable from the beginning and right up to the end. Words fail me in describing this game so here is a link to a demonstration video.
-Click Here-
I watched the video from beginning to end and every second I wanted it more. The game is still unreleased but a release date has been set for September 7th, 2008. I'm counting down the days.