Astronomical Computer from 150 B.C.E.

This is really cool. A British museum curator has built a working replica of a 2,000 year old Greek machine that is actually a precision mechanical computer for astronomical calculations. He spent years studying the rusted and broken pieces of the "Antikythera" that were recovered from under the sea near Greece in 1902.

This is quite impressive, although as some YouTube commenters have brilliantly pointed out, calling it a "computer" is questionable since this primitive device doesn't even support Instant Messaging.