Kilogram. It is the only fundamental SI unit that uses a prefix. And I *believe *it is also the only fundamental SI unit that is based on a physical artifact.
I still like the Parsec. I originally laughed at Han Solo’s “mistake,” then I realised he was from a long ways away and he said that a long time ago. So, it obviously means something else to him.
I think Picosecond should be changed to Picard-second. Being the amount of time needed to decide on Tea! Earl Grey! Hot! whilst pondering beverage choices.
Banana equivalent dose - “additional dose a person will absorb from eating one banana.”
Sunshine unit, now called the Strontium unit - a measurement of nuclear radiation.
Good point.
Smoot’s son attended MIT as well, and I think went to the same frat, so they repeated the experiment with him.
By the way, the markings at the end of the bridge read “364.4 Smoots plus one ear”, which confused me for many years, until I learned that it’s supposed to be “plus or minus one ear.”
a real unit with an interesting history is the barn, a unit of atomic cross-section, which apparently owes its name to the uranium atom being “as big as a barn”, along with the idea of “hitting the broad side of a barn”. see here: Barn (unit) - Wikipedia
and for weirdly-named units, as I’ve said before, you can’t beat radiometry and photometry, which give us:
Candle
Foot-Candle
Candela
Stilb
Phot
Lux
Lumen
Yeah, I had seen that before today, thanks. I was speaking of when I first saw it on opening day in theaters. I still think my 14 yr old self came up with a better explanation than that offered by the gill breathing War-iers on that site. 
I should have thought of this before, but Rhode Island is commonly used as a comparative measure of the size of large sections of ice that break off from the polar ice sheets, as well as for measuring wildfires and other areas of concern.
An asteroid the size of Texas. From some movie …
When I lived out in Utah there was a newspaper column complaining about this practice, which it blamed on Folks Back East. It said something along the lines of “People always compare thingsto the size of Rhode Island, which gets Western folk upset because the fire/iceberg/meteor/whatever is the size of an Entire State. What they forget is that there are counties in the Intermountain West bigger than the “state” pf Rhode Island, so this is causing unnecessary worrying.” Now that I live back in the Northeast, nobody mentions this.
In Texas, from what I hear, there are *living rooms *bigger than Rhode Island.
Centons: either a minute or 100 microns, depending on what you need to measure. Maybe more, if the writers are lazy enough.
The Shitload. It’s a dynamic unit that is larger than a bunch but smaller than a metric shit-ton.
Shitload is also used in a vector quantity, such as a “fuckin’ shitload”. I believe the SI unit is fS.
Back when I was doing graphics, we had a client who always wanted something moved over “just a scosh” (rhymes with gauche). I think it was somewhere between a “hair” and a “smidgen.”
And speaking of hairs, there was the RCH, or “red cunt hair,” supposedly the smallest distance perceivable.
Scosh or skosh is a unit that GIs returning from Japan brought back with them. It’s from Japanese sukoshi, meaning “a little bit”
I had to explain what “RCH” meant to my boss a couple of months ago. Acording to Playboy, the more letters you add, the smaller the unit, as in RBCH for “Red or Black” or RBBCH for “Red, Black, or Blonde”.
Hah! My friends and I used to have a similar unit, except that the hair in question was blonde, not red. I still use that sometimes by force of habit, although I try to watch myself in polite company. It is especially appropriate for very close shaves, like “holy shit, that runaway steamroller missed me by one… (etc).”
Edit: Going by CalMeacham’s post as well, it’s apparently in common use. 
It may not be ‘cool’ but it was very funny to a bunch of high school physics geeks.
My red-headed fiancee assure me that red hair is the thickest the three standard hair colors. I am not a fool and have no desire to gainsay her on this. She says she has empirical data to support her assertion. I believe an experimentation phase should be done by another scientist, namely me. I will report after this weekend.