The Joker's eulogy to Batman. Harley Quinn playing Amazing Freaking Graceon the kazoo had to be done in one take because everyone was laughing too hard afterwards to do it again. Bonus points for the Kick Me sign the Joker put in the casket along with the cape and cowl.
You can hear the voice actress about to fall apart laughing through the whole song.
And the perfect capper:
Joker: ... Well, that was fun! Who's for Chinese?
Like Harley said, Mr. J. knows how to put the "fun" in "funeral!"
Alternatively. Alfred trying to fly the Batwing in "The Forgotten"
Alfred: This must be the place! Bring us down! Computer: Negative. Alfred: But Master Bruce is down here! We have to land! Computer: Impossible. Area too confined. Alfred: Land, you bucket of bolts! Computer: Your funeral. Alfred: Oh dear! Ahhhhh! Get us down! Computer: Caution. Rocks. (Batwing lands in a quarry) Computer: Watch your step. Alfred: (jumbled)I claim this land...for Spain!
Points for Mark Hamill being able to pull that off without laughing halfway through the line.
From a later point in the same episode: "You're going to melt just like a grilled cheese sandwich!"
Also this dialogue:
Joker: We wouldn't want our little caged rodent to suffocate, so we'll just punch some air holes!(Joker punctures the trash can with a dagger while Batman is trapped inside, trying to avoid the blade)
And after he's had Captain Clown throw the trashcan into the ocean.
Oh dear, it seems our air holes are water holes too! Water shame!
Also from that episode - after the climactic fight, Joker is hanging by his shoe over an incinerator and shouts "Batman, you wouldn't let me fry, would you?" Batman takes a moment to think it over with a goofy grin on his face. The Joker shouts "BATMAN!" and seems clearly shocked and offended. It's hilarious.
Yet another gem from that episode involves the Joker looking through the periscope of the submarine he's piloting. He slowly turns it around until he's eye to eye with Batman, who's standing on the roof of the sub. Batman then punches the periscope, and the resulting vibrations hit the Joker right in the face.
A little funnier than that, actually: he turns a good 45 degrees past a clearly-visible Batman, then does a gloriousDouble Take back just in time to get hit.
Nothing quite compares to how The Joker escapes at the beginning of "Christmas With The Joker." Escaping from Arkham Asylum? Fairly standard. Doing so on a rocket shaped like a Christmas tree? Inspired. Doing so while singing "Jingle Bells, Batman Smells", and actually escaping on the line "And the Joker got away"? Gut-bustingly hilarious.
The episode "Almost Got 'Im" to be one of the funniest episodes in the series. Just the witty banter between the the villains is enough to leave her in stitches. But, the funniest bit would have to be when Harley Quinn starts reading from the phonebook in a hilariously deadpan tone.
There's also Croc's brilliant Death Trap plan, told in an attempt to upscale Poison Ivy and Two-Face's elaborate attempts.
Killer Croc: There I was, holed up in this quarry, when Batman came nosin' around. He was getting closer, closer... Poison Ivy: ...And? Killer Croc:I threw a rock at him! [Chirping Crickets] Poison Ivy: *Ignoring Croc* So, Harvey, what became of the giant penny? Killer Croc: ...It was a big rock...
Bonus points that Killer Croc was actually Batman in disguise.
And it got even better during "The Trial", because the real Killer Croc's suggestion to dispose of Batman was simply "Hit him with a rock!"
and what happened to the giant penny Two Face tried to kill Batman with?
Two-Face: They actually let him keep it!
From the same episode:
Two-Face: Poison Ivy... Poison Ivy: It's been a long time Harvey. You're still looking half-way decent. Two-Face: Half of me wants to strangle you. Poison Ivy:(flirtatiously) And what does the other half want? Two-Face: To hit you with a truck! Poison Ivy:(to the others) We used to date. Joker/Penguin:(understanding) Ohhhh.
"Beware The Creeper!", notably because of his ransacking of an upscale clothing boutique looking for a new superhero outfit, a scene which gave us the character Thriftie, the clerk with the green sweater, green headband, and biting stone-faced stoicism. Never once in the entire scene does she even raise an eyebrow at Creeper's actions; instead she answers each one with a snarky comment that's snarkier than the last.
Even Alfred gets in on it:
Alfred: The police just received a call about a giggling lemon-yellow maniac trashing a thrift shop. But here's the strange part...
Harley: Did you see the way I handled those creeps? Pow! Bam! Batgirl, eat your heart out!
Robin: What was she before she went bonkers?
Batman: A clinical psychiatrist.
During the episode while sneaking in Harley follows after him whispering "Sneak Sneak Sneak Sneak" only for Batman to whip around and glare at her and she instantly shuts up.
"Harley's Holiday": The Scarecrow is getting hauled back to Arkham by Batman and Robin.
Scarecrow: I am the master of fear! The lord of despair! Cower before me and witness terror! Harley Quinn: Hi, Professor Crane! Scarecrow: (rather sweetly) Good evening, child... (back to ranting)Worship me, fools! Worship me! Scream hosannas of anguish to Scarecrow, the all-terrible God of fear!
It's especially funny because it shows that Batsy's insane rogues actually have a semblance of a normal (to them) society within Arkham. In Joker's Wild, they fight over what TV channel to watch like a dysfunctional family.
And immediately afterward, Robin points a thumb at him as he's dragged down the hall, and nonchalantly remarks, "I think he's getting better!"
Same ep, right after snapping in a clothing store over a misunderstanding regarding a dress.
Harley: Watch it buster, I'm armed! (smacks Bruce Wayne with mannequin arm)
The crowner — in a whole episode of Crowned — has to be when Harley and Veronica are almost out of Gotham — and the "kidnap" victim Veronica has made her peace with Harley. Harley tempts fate by saying that for the first time today, things look good. At which point, the car is almost blown to bits by a cannon shell. Dazed, Harley sees Veronica's father, an army general, whipping a tank like the old cavalry man he is and bearing down on them.
Harley: "Daddy? Oyyyyy..." (She rapidly turns the car back towards Gotham.)
Harley proudly showing her Certificate of Sanity to Veronica the same way you'd show a diploma or first driver's license.
The face Bruce makes when he's dragged away by Veronica, clearly showing he'd rather spend time with the ex-clown girl who tried to kill him numerous times.
The ending where Harley kisses Batman who is too stunned to react twice is just hilarious - especially with Poison Ivy and Robin standing in the sidelines, sharing a look that pretty clearly says: "What the?" Doubly funny if you take the classic Ho Yay and the newer Les Yay into account.
How about the Joker's answering machine message? It's either hilarious or creepy, depending on where he got the recording. As follows:
Joker: " *Evil Laugh* Boy, did YOU get a wrong number! Leave your message at the sound of the shriek."
Male Voice: "No... please... don't! AAAAAAAAAAAAAAAAAHHHG!"
In "Trial": Harley going nuclear on the Joker.
Janet: Sad, isn't it? Harleen Quinzel used to be a doctor here at Arkham, until the Joker twisted her mind.
Harley: Ha! You're just jealous 'cause you don't have a fella who's as loving and loyal as my pudding is to me!
Janet: Uh-huh. And I suppose it's that same loyalty I saw the last time you escaped...
(Joker frantically waves his hands trying to signal Janet to shut up)
Janet: ...and puddin' here finked on you in hopes of getting time off.
Scarface: And now, all greet the most benevolent, most fair Judge Joker!
Joker: (Slams the hammer down) GUILTY!!!
Another "Trial" one, after Janet has provoked a rant from Mad Hatter:
Mad Hatter: Umm... I'd like that stricken from the record, please. Joker: Record? Is someone supposed to be writing this down?
In "Holiday Knights", Harvey Bullock is posing as a Mall Santa. This is funny enough in and of itself, but here's a conversation between him and a little girl who comes up:
Girl: My name's Mary MacSweeney. Can you bring my Daddy home for Christmas?
Bullock: Gee, kid, I dunno. Where is he?
Girl: (cheerfully) In prison.
Bullock: You mean your dad is 'Mad-dog' Mac-...I mean, Mike MacSweeney?
Bullock: Uh, listen, kid, it's like this. I, uh... ah... I'd like to help you out, but... er, uh, what I mean is... (gives up) Sometimes even Santa can't make every wish come true. (reaches into pocket and pulls out a handful of bills) Here kid, buy yourself something nice."
Girl: Thank you, Santa! (hugs) Can I buy my Daddy something, too?
Later in that segment, Clayface shows up. Batgirl knocks him into the ice-skating pond outside, which he breaks through. There is a Santa on the chain of lights above the rink. Bullock and Montoya try to shoot Clayface.
Batgirl: Don't waste your ammo on him! Shoot the Santa!
(Montoya and Bullock look at each other)
Bullock: You wouldn't.
This little scene:
Obnoxious kid: You're not Santa!
Bullock (dressed as Santa): Sure I am! Wanna see my gun?
During the shopping montage, they cut to Bruce signing various checks and receipts, with a look on his face that says he's gonna murder those two as soon as he can get back into a cowl.
Another Harley moment from same episode, she kept BEGGING Ivy to get them a Christmas tree, to which Ivy said no-saying that the tradition of Christmas trees is Genocide to the Pines! When they kidnap Bruce and make him pay for their shopping spree, the first thing Harley notices is a Christmas tree...
Ivy: (grabs Harley by her jester hat, and drags her off screen) NO!!
And when a Christmas tree falls on them, a grumpy Ivy points out that Harley got her tree, and asks if she's happy now. "Yeah," Harley answers with a sigh.
Joker's reaction when his New Years scheme concludes with a bell being dropped right onto him. Even Batman flinches.
Although it was only an experiment, someone from 4chan's /co/ board adding more Batman Glare into the intro.
The top rated comment:
Keep in mind he didn't actually take down the thieves himself, he actually shot a batarang out of his eyes to knock the guns out of their hands and then glared at them so hard he shot ANOTHER Batman out of his eyes to beat down the crooks for him.
I dare you to prove me wrong, I DOUBLE DARE YOU MOTHERFUCKERS!!!
In Batman: Mystery of the Batwoman, Batman breaks into a suspect's apartment and is going through her wardrobe when her bodyguard walks in on him. It should be mentioned that this is a bodyguard whom Batman thoroughly thrashed in an earlier meeting. They stare at each other for five mute seconds, then the bodyguard calmly closes the door and walks away. The bodyguard's partner asks what's up and the bodyguard says: "Nothing."
One classic bit that was completely unexpected takes place in "See No Evil". While Bruce is at a jewelry store, the villain of the day enters the men's room to change into his invisibility suit and locks the door when a poor guard needed to use the restroom. When he tries again later, Bruce is in there getting changed into the Batman costume. This time, the guard waits in front of the door, to which Batman slams it open and just smacks the poor guy against the wall.
Hobo: I didn't know he could fly too. (the other hobo shrugs)
The Clock King scores one in "Time Out of Joint". After activating his device that causes time around him to slow down, he decides to take the elevator to the top of a building... only to realize how pointless this is and takes the stairs instead.
And in "The Clock King" before he became the title character, he takes Hill's advice and takes some time to himself. So he goes to the park and just sits there, unsure of what to do now that he actually has some spare time. It's funny and almost adorkable in a weird way.
Girl's Night Out
Livewire: Are you out of your mind?
Harley Quinn: (with a grin after thinking for a second) Yeah!
Gambol: You think you can steal from us and just walk away? Joker: Yeah.
Harley insists on using a giant mallet for a robbery. Poison Ivy uses her trademark vines to bust an ATM, while at another, Livewire uses her powers to demonstrate a much simpler process. Harley is at another ATM..... hopelessly pounding away with a giant mallet.
Ivy: ...at least she's consistent.
In "Chemistry" when Bruce is talking about Susan:
Bruce: It's a lightness. A sense that things will work out for the best.
In "Riddler's Reform," Riddler's poleaxed reaction (with a mental "twang!") to the approach of a beautiful woman at a party.
Woman: Where did you find him, CB? He's so adorable.
Riddler: Who? (glances around) ... me?
Then later, he beams with adoration in a mirror and agrees:
"You are adorable!"
A moment in "Never Fear": A Batman with his fear of killing chemically removed strangles Scarecrow unconscious before Robin manages to hit him with the antidote. They're all on a runaway train—
Batman: You're going to have to jump!
Robin: What about Scarecrow?
Batman: I'll take care of him!
Robin: (wordless appalled look)
Batman: ... I'll get him off the train!
In that same episode when Bruce saw Tim playing around in his office.
Bruce: Playing hooky again?
Tim: It's summer vacation. How could you forget?
Bruce: (stern expression on his face)
Tim: Right, I forgot who I was talking to.
"Legends of the Dark Knight." Silver Age Joker goes through the effort to take the guard's keys, makes a joke that he has the keys, and then proceeds to smash the display case of what he wants instead of using the keys.
In "Fear of Victory"—
Batman swings through a window into a woman's apartment. Even when he's not Bruce Wayne he still gets the ladies:
Woman: Oh my!... (seductive pose) Oh, my.
Batman lies in wait for the Scarecrow to deliver a fear toxin-laced telegram to a sports star. Instead, when a telegram arrives, he catches an ordinary courier who panics and promises not to double-park anymore.
"Mad as a Hatter": Alice Pleasance's fiancé has broken it off less than twenty-four hours after he proposed. She comes home to a house full of flowers and her previously "sweet, funny" boss being a little too excited about the prospect of catching her on the rebound (plus he inexplicably knows about the breakup). Then, while backing away from him, she bumps into Batman. Her reaction? "Oh, this is getting too weird."
Tim: I know [the American justice system] is bogus.
Bruce: And how did you come to that well-thought-out conclusion?
Tim: (smug face) Watching you.
The best part was Bruce's dumbfounded expression and had no other way to counter it other than to change the subject. Yes, young Tim Drake just stumped the Batman...awesome AND hilarious!
After Batman's umpteenth Stealth Hi/Bye on Gordon: "One of these days I'm going to nail his shoes to the floor!"
The Funny Background Event during the opening news report in "Heart of Ice," where a cop tries to chase some kids away from a crime scene, only to get pelted by snowballs once he turns away.
In "The Laughing Fish," Harley repeatedly expresses her disgust of fish, until the Joker says he'll make it up to her by letting her be his mermaid... and slips a fish head costume over her. Harley gives a Death Glare and says "You're really sick, you know that, boss?" It's also possibly a reference to Red Dwarf.
From the same episode, when Batman brings in a Joker fish to be analyzed:
Alfred: This could cause a stampede to pork.
Joker: "Colonel What's-his-face gets chickens, and they don't even have mustaches!"
After dealing a vicious fate to a robot duplicate of Bullock, Batman is faced with Barbara demanding he let her help him. His response: "Please let go of my cape."
In "Sins of the Father", the moment where Two-Face asks Tim where his father is.
Two-Face: Now, talk. Where is he?
Tim: How 'bout I go check his calendar?
Two-Face: (slaps Tim with his glove) He stole something from me.
Tim: Your charming good looks?
"Joker's Millions" has Batgirl commenting that with Joker being rich, maybe he'll give up crime. This is made hilarious when Batman snaps the object he's working on upon hearing that statement; the look on Batgirl's face is really priceless. She then comments of going with Dick to the Iceberg Lounge...
Later on, she makes a comment about how the Penguin(currently in his regular disguise) wouldn't stop Gordon's daughter from entering his lounge... His reaction sells the moment
When Ernie, Joker's lawyer, suggested of going back to crime.
Ernie: Maybe you can pull on of those classic routines like that laughing fish.
Joker: Good idea, Ernie. Just let Batman know I did it SO HE CAN KICK MY KEISTER RIGHT BACK INTO ARKHAM! (pushes Ernie) Dope.
Also, Batman interrogates Ernie later on by giving him a swirly. At first, the Penguin plans on stopping him from mistreating a guest, but backed away from the bathroom door once he heard it happening.
In the episode Bane, Batman finds the Batmobile smashed by the episode's namesake:
Batman: He trashed my car, Alfred. Between a couple of guys, that's real personal.
In Feat Of Clay Part 2, Roland Daggett's germophobic henchman, appropriately called "Germs", shows concern about infiltrating a hospital ("all those sick people...") but does it, with some fear. Batman chases after him, eventually cornering him in the room where they keep disease samples. Germs presses himself to the far wall, frantically looking around at the samples. Batman picks one up at random — "Crimson Fever. Lousy way to go. No cure, you know." — then places it on a shelf over Germs's head and starts asking questions. For every lie, he bangs the wall, and the jar comes one step closer to falling. Just before he's got his information, a security guard interrupts, saying that he'll take it from here. Batman slams the wall one final time, and Germs yelps and cowers as the jar tumbles...but Batman catches it before it hits him. The scene lingers on that shot for a little bit longer — enough for the viewer to see that the label reads "Seawater For Analysis". Subtle, but hilarious.
In Joker's Favor, Charlie Collins, the man the Joker forced into helping his plot, threatens him with one of his bombs. After being unable to convince him to stop, he starts calling Batman for help. Then it turns out that not only was Batman watching the whole time, but the bomb was fake. Batmanlaughs at it! Doubles as a Moment Of Awesome, as Batman then tells "Mr. Collins" to go home with the same respectful tone he generally reserves for Gordon.
The Joker's 'subtle' way of calling for help:
Joker:[Nervously] Look Charlie, you had a busy day. All this excitement, all this running around with BATMAAAAAAAAAAAAAN!!!
A background gag in "Beware the Gray Ghost" when Alfred and Bruce go to a video dealer. Alfred notices the dust on the counter and instinctively starts dusting the counter with a handkerchief.