Actually, it's just the case that's really made out of Legos, the rest are your usual computer parts. However, for once there is a Lego DIY project that isn't multi-colored.
The ones that have all of the different colors tend to make it look even more like the project of some prodigy ten year old. This one is all black and for once looks like something an actual adult might create.
The project was done by Luke Anderson who was nice enough to post a full guide on how to do this project yourself. He also has a time lapsed video of him assembling the case, which comes complete with techno music. He created the computer specifically as a web/development server and wanted one for a decent price. You can check out his full guide here.