They say life was better in past times, and for computers this is true, as they were used for something useful instead of surfing for pr0n. Michael Wright, a former curator of the Science Museum in London, rebuilt a 2,000 year old Greek machine that can be considered as the world's first computer. Called Antikythera, the machine was used to track the movements of the planets known to humankind back then.
There is also a video showing how it works.
via Unhandled Perception