The file Kaiser has on the Joker includes his real name as Jack Napier, from the first Batman movie.
When Bruce starts to realize the plan of Kaiser and moves the paper on the wall, that paper suddenly changes from being purple to purple & red with spades and clubs
LOOK HARD: Joker's not the only one who can cheat at cards. When Bruce checks his cards the first time, he has a 9 and a 3 (12). When he receives a King from Joker, he replaces the 9 with an 8, making 21. He later hands off a deck to Alfred.
The sign that Joker throws off the car he steals at the casino incorrectly reads "WAN THE CIRIN GNAL JOKERNOCILE."
JOKER: Don't look now, Sonny Jim, but the Plant Lady's gone wackers again.
Poison Ivy : He started it! I was just sitting here!
JOKER: That's right! You're always blaming me! And the children wonder why we fight.
Joker: (About Kaiser) He's ripping me off. I'll protest. Yeah. I'll sue. Then I'll rip his lungs out. And I will too.
TV: Next, a dog drinks milk out of his owner's mouth.
Joker: Oh, please, Mr Kaiser! You of all people should have realized there'd be a Joker in the deck!
Joker (After Seeing Batman flying outside the helicopter) Why Can't He Ever Stay Dead?!
The Joker: Jumpin' 'uminy Christmas! It's an homage to me! I'm kinda sorry I have to blow it up.
Joker: If you try and hold my hand, I'll slug you.
Poison Ivy: Guard!
Joker: All right, all right, just kidding.
Joker: Step right up and play everyone's favorite game, folks! "What's the Joker got in the Pail?" Could it be a deadly poison? Or just something to make the floor nice and slippery?
The Joker: (escaping from Arkham) I always did know how to make an exit.
The Joker: Good evening, folks! The game is blackjack - Joker's rules of course. (chuckles)
Batman: He's counting on you to blow this place up so he can collect the insurance. By the time you get clear, Kaiser will be miles away laughing at you.
The Joker I hate it when you make sense!
This episode is episode 13 on the Batman: The Animated Series Volume 2 DVD.
You can see the Mad Hatter and the Scarecrow playing chess next to Poison Ivy and the Joker.
When Joker changes the television channel and Poison Ivy tells him to change it back, Joker says "Oh, no, no, no. Don't want to." using a line of and the voice of Beaky Buzzard, a character that appeared in several classic Warner Brothers cartoon shorts.
Beaky's voice was patterned after Edgar Bergen's character Mortimer Snerd.
When the Joker enters the Patients' Lounge in Arkham Asylum, he is whistling 'The Merry-Go-Round Broke Down' by Cliff Friend and Dave Franklin, which is best known as the theme to the Looney Tunes animated shorts.
TV announcer: Next a dog drinks milk out of this owner's mouth!
When the Joker switches channels, you can hear a voice announcing David Letterman's DC analog hosting Stupid Pet Tricks.