This is not the first song about the calendar, either:
(excerpt from Zappa's Greggery Peccary):
...
G.P. I must plummet boldly forward to my ultra-avant laminated simulated replica mahogany desk with the strategically placed, imported very hip water pipe, and the latest edition of the "Whole Earth catalog", and rack my agile mind for a spectacular new trend, thereby rejuvenating our limping economy and providing for bored miserable people everywhere, some great new thing to identify with.
Stenographers: We have got all the little answers to the things that might be bothering you.
G.P. We have got your little toys. (We're busy makin' 'em)
Stenographers: Busy makin' 'em. Where is he making them.
G.P. Busy making them, just for you. Highly efficient Mrs Snodgrass.
F.Z. And with that, Greggery turned & strode nonchalantly into his
dinky little office, with the desk, and the catalog, and the
very hip water pipe, and proceeded with a vigor and
determination know only to piglets of a similarly diminutive
proportion to single-handedly invent the calendar. With his
eyes rolled heavenward, and his little shiny pig hoofs on the
desk, Greggery ponders the question of eternity, and
fractional divisions thereof, as mysterious angelic voices,
sing to him from a great distance, providing the necessary
clues for the construction of his new thrilling new trend.
G.P. Sunday, Sunday, whow.
Sunday, Saturday, Tuesday through Monday, Monday.
Sunday, Saturday.
F.Z. And thus the calendar, in all of its colorful disguises, was
presented to the board and miserable people everywhere.
...