FurlongsPerFortnight is the most standard of the nonstandard units of speed in physics and engineering.
I don't know where it came from, but i know it's well-known: my oldest unix memory is BruceAnderson (a physicist by degree) showing me how to use the unix 'units' tool to find the speed of light in furlongs per fortnight, and my physics teacher at school certainly recognised the unit. Google for the term and you'll find it's quite common. -- TomAnderson
http://www.jardine-electronics.com/written/furlong1.html
http://www.aip.org/enews/physnews/1999/split/pnu409-3.htm
I have a notion that it first appeared in the original Journal of Irreproducible Results, but I can't prove it.
If I haven't messed up my calculation, a furlong per fortnight is approximately 1.663 x 10^-4 metres per second. Almost exactly TenMillimetresPerMinute?, to preserve the alliteration. --KarlKnechtel
Oops, yes, ten rather than one. Oh well. :)
There's an entire replacement for the M/K/S (Meter/Kilogram/Second) system of measurement; the FurlongFirkinFortnight? system of measurement--wherein the furlong is the base unit of measure for distance, mass is measured in firkins (technically, the firkin is a measure of volume, so the mass of a firkin of water is used), and the fortnight is used for time.
Have no idea what they use for temperature (Farenheit?), electrical current, amount of substance, luminous intensity, planar angle, or solid angle.... oddly enough, I couldn't find any documentation on the FurlongFirkinFortnight? system on the web.
See: WhimsicalUnitsOfMeasurement
CategoryWhimsy, CategoryIdiom (as used in The Good Ol' US of A)