now, you see--jokes come in many forms, and the "scrod" joke is one that has SO many variations....a Google search on the term "get scrod" will get you an amazing assortment:
..here is just one.

"A businessman arriving in Boston for a convention found that his first evening was free, and he decided to go find a good seafood restaurant that served Scrod, a Massachusetts specialty. Getting into a taxi, he asked the cab driver, "Do you know where I can get Scrod around here?" "Sure," said the cabdriver. "I know a few places... but I can tell you it's not often I hear someone use the third-person pluperfect indicative anymore!"

I personally heard the punchline 25 years ago as "Past pluperfect subjunctive"...