The kids at Outerra aren't out to do much. Only create a game engine that can create entire planets for you to mess around in.
An indie project, the goal is to build a "3D planetary engine for seamless planet rendering from space down to the surface". Which means build a whole planet, letting you start it in orbit then fly it all the way down to the surface, with no loading times and no artificial walls.
Once the planet is rendered, Outerra claims to then be able to run, well, a game on top of it, with vehicle physics and 3D object importation ready to go.
It's an ambitious goal, one that's been the dream of game designers -- including mythical space MMO Infinity -- for decades. Hopefully these guys can pull it off!