Machinima

Machinima is a kind of animated film made using a computer game engine to generate the characters and environments.

Read about Machinima at: Wired

Take a look at an example of Machinima: Dracula's Guest

Also: Movies

Want some more? There's a whole film festival build around Machinima: Machinima film Festival 2006

If you love gaming and you are interested in making some Machinima of your own, here's a place to start: Machinima.Org