John Carmack, id Software co-founder and technical director, was unveiled as a surprise guest during Apple CEO Steve Jobs' keynote at this year's Worldwide Developers' Conference. While that may not be big news in and of itself to most readers, what Carmack brought to the keynote is.

What we've got here is the entire world with unique textures, 20GB of textures covering this track. They can go in and look at the world and, say, change the color of the mountaintop, or carve their name into the rock. They can change as much as they want on surfaces with no impact on the game.