The smoot is a nonstandard, humorous unit of length created as part of an MIT fraternity pledge to Lambda Chi Alpha by Oliver R. Smoot, who in October 1958 lay down repeatedly on the Harvard Bridge between Boston and Cambridge, Massachusetts, so that his fraternity brothers could use his height to measure the length of the bridge.
What was the prank?
https://en.wikipedia.org/wiki/Smoot
The 83 year old Smoot is still alive, and his career was as a chairman of two standardization organizations. Pretty funny.