A reader:

”**ROBERT** Burton? C’mon Derb, it’s 9.30. Finish mudding that drywall and correct this heinous mistake, or your name will be mud!”

[Derb] Yeah, yeah, this isn’t the bloody New Yorker, you know.

As to that joke: If I tell you that the last word in it is the third person plural, present indicative, of the Latin verb “esse,” you will probably be able to reconstruct the whole thing.