4600-odd years ago, Huang Di, China's legendary Yellow Emperor, conceived the idea of building a chariot with a pointer on it, geared so that no matter how the chariot moved, the pointer would continue to point south. A scholar named Fang Bo managed to build the thing, and, according to legend, it actually made a difference in a military campaign.
The gadget itself disappeared, and has been reinvented several times since then, most recently by George Lancaster in 1928; since then MANY variations on the theme have been designed and built; see here: http://www.odts.de/southptr/
These are cool little toys, and I have an urge to dig my LEGO out of the vault and build one, just because.
While researching South Pointing Chariots, I came across a speech by inventor Dean Kamen, in which he describes the chariots, and then points out that the Chinese already HAD the magnetic compass when the South Pointing Chariot was developed. He stated that inside his shop, "South Pointing Chariot" has become slang for a technically sophisticated but ultimately pointless idea, and he encourages his workers to avoid such things.
I am not sure whether I should laugh or cry at this; given that Kamen is the inventor of the Segway, probably the most famous example of technically sophisticated and completely pointless gadgets in years... It would seem that Kamen is some sort of champion of clueless irony...