The Moon: Earth's Sneezeguard
Mandi Walls writes "SF Gate is running an article about looking on the moon for pieces of Earth that may have been knocked into space by collisions with asteroids, etc. The article claims the guys responsible for the idea came up with it while stuck in traffic. They were probably digging for change for a toll in the seats."
This clue led to the discovery that an object will displace its volume when immersed in a liquid.
I don't think that Archimedes's discovery was that a submerged object will displace its volume in water (that's pretty obvious), but rather that a *floating* object would displace a volume of water of the *same weight* as the floating object (a much deeper result).