Also known for "First actual case of bug being found" note
9th of September is considered to be the "QA day" in Russia. Why? Because of this anecdotical story mentined in jargon file featuring Grace Hopper.
Technician solved a glitch in the Harvard Mark II machine by pulling an actual insect out from between the contacts of one of its relays. The text of the log entry (from September 9, 1947), reads "First actual case of bug being found".
But if you read Wikipedia article about her, you will learn that she is famous not only for this (note that it wasn't actually her who found the bug, she is just known for telling this story), but actually she had quite some ground-breaking ideas, including, for example, idea of compilers. Just try to imagine it:
It's not people, but computer programs who should create computer programs.
Sounds good even now, heh?
So she is one of authors and promoters of COBOL programming language, which became quite popular back in 60s and is still used in old systems today.