FRESHI NOW RECOMMENDED LINK: MACHINIMA.COM

Here's the Wikipedia entry:

Machinima (pronounced /məˈʃiːnɨmə/ or /məˈʃɪnɨmə/) is the use of real-time three-dimensional (3-D) graphics rendering engines to generate computer animation. The term also refers to works that incorporate this animation technique. Machinima-based artists, sometimes called machinimists or machinimators, are fan laborers and often use graphics engines from video games..."

In other words, Machinima involves taking existing 3D video game environments and creating new "films" by manipulating the characters and scenes within those games.

Machinima.com is a vast site devoted to this creative environment: "Machinima.com is the premier online entertainment network showing trailers, gameplay, montages & original series created in video games."

if you're completely new to this, be sure to check out the Machinima101 section.

Finally, check out their YouTube channel at http://www.youtube.com/machinima