Machinima is basically the art of using a video game to construct a film. Typically, one player is the camera, while the rest are the actors. Over the years, game quality has improved, and therefore the quality of machinima productions have skyrocketed!
One, by Robert Stoneman, is the best machinima production I have seen to date! This short file was built in Battlefield 3, which features some of the best lighting and textures in the industry, and the cinematography is beyond description. You’ll just have to see it for yourself.