CryEngine 3, the graphics engine behind the recently released Crysis 2 was made available to the public for free just five days ago. It's already hit a casual 100,000 downloads.
The SDK was made available for free for non-commercial use, so if an indie dev does manage to strike it big they will be handing over a 20% cut of revenues.
With 100,000 downloads we expect to see at least 50,000 awesome looking indie titles by this time next year. We can only dream.