You simply have to see this. Thanks to 14theditch Jeff Ford for the link!
The Antikythera mechanism is a gearworks computer showing the phases of the moon and the location of the planets in a geocentric universe. They used to think it was 1st century B.C., but now they're thinking 2nd century B.C. Either way, it's a thousand years ahead of its time, even if they are thinking it was more of a rich guy's toy than an astronomical tool.
Impressive, young Jedis.
Now For The Speculative Twist
If the Antikythera mechanism is considered to be a thousand years ahead of its time, what piece of tech -- or tech hiding as a toy -- would be something a thousand years ahead of its time today?
For me, it's easy. In my 29th century SF universe we have interstellar travel, accidentally discovered in the 2200s. But even that isn't really a neat little clockwork simulated universe box... (grin)