For those interested in learning, Epic now provide the UDK (Unreal Development Kit) for free to those who wish to use it in non-commercial capacity. This means

For those interested in learning, Epic now provide the UDK (Unreal Development Kit) for free to those who wish to use it in non-commercial capacity. This means that whilst you can't sell anything you make with it, you can get your hands on the full Unreal 3.0 engine that powers many modern games (eg. Gears of War, Bioshock 2), and do whatever you like with it. Great for prototyping, experimenting and generally learning about game development.