Illegitimi non carborundum, mock-Latin for "don't let the bastards grind you down", dates to early WWII, and later in the war was adopted by Gen."Vinegar" Joe Stillwell as his motto. For more, including variants, see Wikipedia.
Do users have any other well-known examples of this type: an English phrase translated into mock-Latin? It should be pithy and witty. Maybe the example I have quoted is sui generis.
Let's accept that it could be dog-Latin and that it is possible to dog-Latinize anything, anything at all. I'm not asking obscure dog-latinized doggerel.
I'm also not asking for a standard Latin aphorism known to Cicero. There are plenty of those, and they are easy to find.
Annus horribilis is not exactly what I was asking for, but it is close. Pithy, witty, not a standard Latin phrase, well-known. Illigitimi non Carborundum is of the same family, but a different species. I'll settle for canid, not necessarily canis familiaris.
Best Answer
One recently coined Latin expression that became very famous in 1992 was Queen Elizabeth's annus horribilis, meaning “a horrible year”. Although not "mock Latin", it was not an aphorism used in ancient Rome.
Another pseudo Latin aphorism, one which Harry Potter fans will instantly recognize:
Draco Dormiens Nunquam Titillandus
It is the motto of Hogwart's School of Witchcraft and Wizardry and stands for “Never tickle a sleeping dragon”.
This invented Latin phrase tickled my fancy, Mellita, domi adsum; “Honey, I'm home.”
Other amusing phrases from Latin for All Occasions, by Henry Beard can be found here.