Back at the beginning of time, Dick Cheney and the Devil were making the universe and they both liked using the metric system. Cheney had 66726 fingers on his hands and the Devil had 299792459, so the Devil said "Look, you count the freckles on my buttocks and we'll make the day have that many seconds---then we'll set it up so the speed of light is 299792459 meters per second and you can make the gravity constant whatever you like, agreed?"
Cheney thought that was fair enough so he counted the freckles on the Devil's behind and found there were 86400. They made day have that many seconds and then he pressed the green button on the console to establish the fundamental constants and get the universe started working. However due to roundoff error in establishing h-bar it turned out that when spacetime and everything had all been created they checked and found a MISTAKE: the speed of light was only 299792458 meters per second.
The Devil was bitching and moaning and threatening to sue Microsoft and Cheney said "Damn, I'm not going to re-compile just to fix the last digit! Give me your hand here so I can count the fingers again." He was pretending to count the Devil's fingers when he saw the Devil wasn't watching, so he grabbed a cleaver and chopped one off.
That is how Cheney solved the problem. It explains why the Devil only has 299792458 fingers and why, if you express it in metric terms, the gravity constant turns our to be 66726 cubicmeter/squaresecond per exagram. As good metric users know, exagram (Eg) is what the metric governors like you to say for quadrillion kilograms—they "deprecate" anybody who says "terakilogram" so be sure you always say "exagram". The 1986 CODATA recommended values of the constants are used here out of respect for everyone's conservatism.
Note: in the units used for most of these stories the speed of light is 10 million miles a minute (compare 10 000 000 with 299792458) and the gravity constant is 1.00 mile3/minute2 per quadrillion talents (one instead of 66726, or 66730 as CODATA recommended most recently.)