Quotes Uncovered: The Origins of Couch Potatoes

Photo: Dag Terje Filip Endresen

I’m back to inviting readers to submit quotations whose origins they want me to try to trace, using my book, The Yale Book of Quotations, and my more recent research.
Mantonat asked:

Any idea as to where the phrase “couch potato” originated?

The Oxford English Dictionary says that “potato” here is apparently a pun based on “boob tuber,” but it could also be a simple association with the slang use of “vegetable.” The earliest citation for “couch potato” in the OED is the Los Angeles Times in 1979.
Drew asked:

Was “Statistics are like ladies of the night … Once laid out you can do anything with them” really Mark Twain?

No.
Do any readers have any other quotations whose origins they would like me to attempt to trace?