From tonights Christmas episode:
Lisa: “You never mentioned a brother before!”
Grandpa: “And I’ll never mention him again.”
Grandpa’s service record.
In WWII he’s been an infantryman on the German front, a minesweeper (whose incompetance earned him an Iron Cross), a sailor under JFK on PT 109, and a Navy pilot in the Pacific. In WWI he lied about his age to get in (being a toddler at the time) and also invented kissing as a means of germ warfare.
What I don’t get is, if he was only a toddler during WWI, then how did he chase the Kaiser for diggity-three miles to get back our word for twenty?
I believe it was sold in a yard sale. At least it was on sale when Gerald Ford came to town.
I think we did see it down there at least once.
They had one of these jokes in yesterday’s Christmas episode, even though I think it was suppoesd to be outside of continuity. Grampa starts talking about his brother Cyrus, and Bart and Lisa say “you’ve never mentioned Cyrus before.” Grampa says something like “And I never will again. I loved him so much…”
In one episode he says he spent the war as a cross-dressing cabaret dancer in Germany.
“Ach! Eine Boobie!” - Hitler.
That story was only mostly true, though. Abe admitted that he did wear a dress for a time in the 'forties.
A less prominent one than Burns always forgetting about Homer is Krusty always forgetting about Bart
I just recently reviewed the episode where Bart is the “I Didn’t Do It” kid. He sneaks away from the box factory tour to the TV studio and helps Krusty, who doesn’t recall him despite Bart rattling off all the times he’d pulled his ass out of the fire (keeping him from getting framed, helping his reconcile with his father, etc.).
There’s also IIRC a callback to the joke in the flashback episode where Homer gets the job at the plant – there’s that great speech where Homer barges in to Burns’ office and forcefully tells Burns that he’ll be the most toadying sycophantic employee ever, “and if you don’t like it, I’LL CHANGE!” After Burnes gives Homer the job and he leaves, Burns says “Simpson, eh. I’ll remember that name.”
Of course it’s been years since I saw that episode, so I may have made that whole thing up. 
–Cliffy