Halo (series)/Funny

"I would have been your daddy, but a dog beat me over the fence!"
Sergeant Johnson

The random lines of dialogue spoken by NPCs in Halo are among the funniest things in all of gaming. In this troper's case, he was playing Halo 3 and was killed after a protracted battle with a gang of Brutes. After dying, one of the Brutes ran over, stood over the Master Chief's corpse, and said, "He's dead! Now, we cuddle!"
- "I need a nurse! No, no, a female nurse."
- "Can I have his helmet?"
- "CHARGE! ...BACKWARDS!!!"
- "HE WAS MY LOVER!"
- Even better is that there's a special skull in some games the reverses the chances of saying these lines, meaning they come up more often.
The enemy dialogue in Halo 2 and 3 can be pretty humorous. One that comes to mind is one of the elites' reactions to catching a grenade blast: they yell, in their typical, over-the-top, hammy way, "I'm seeing double!!!"
The cutscene before the level Keyes in the original game was funny; Cortana thinks she's figured out how to Teleport the Chief. She manages to do it, but she mistakes the ceiling of the ship with the floor.
- No, the funny bit is immediately afterwards when that mistake finally exhausts the Chief's patience and he Dope Slaps his own helmet to shut her up.

Cortana: "Oh now I see, coordinate data needs to be" * donk* "Right...Sorry?"

In the level The Maw (the last level in the game), Cortana's trying to tell the Chief to pull up on his hijacked (and heavily damaged) banshee or else they'll crash, while Chief casually disregards this. They end up crashing, the Chief none worse for wear, and Cortana betting that he did that on purpose.
You can find many voice outtakes on Youtube; which can be downright hilarious. My personal favorites are the "Corpse-Man" tirade and the "Bet you can't stick it" line.
When Master Chief thought he'd shoot his way out, mix things up a little bit.
This Troper especially enjoys Sergeant Johnson's inspiring pep talk to the marines at the beginning cutscene of the first game, and all the variants therein:

Normal: "When we meet the enemy on the ground, we will rip their heads from their spines, and toss them away, laughing!"
Legendary: "I don't care if it's god's own anti-son-of-a-bitch machine or a giant hula hoop! WE AIN'T GONNA LET 'EM HAVE IT!!! What we will let them have, is a belly full of lead, and their own blood to drown in!!"

- "Am I right, marines?"
  - "SIR, YES, SIR!
In ODST, just watch the Rookie's reactions to Buck and Dare's arguing. And Dutch's prayer at the end of Uplift reserve is also hilarious.

"Uh... Lord? I didn't train to be a pilot. Tell me I don't have anymore flying to do today" * drone-fighter crashes into a nearby statue* "...So, is that a yes or a no?" * behind him, his vehicle randomly explodes* "(Smiling) Amen."

"Get...this thing...off...of me."
"Take my advice, Rookie. If you ever fall for a woman... make sure she's got balls".
After Romeo takes out an Engineer-spawning building:

Dutch: Well As the Good Book Says..., payback's a bitch!
Mickey: I don't think it actually says that, Dutch.
Dutch: I'm paraphrasin', ya heathen!

The three versions of the password door in Halo 3. (This is improved by the fact that all of them are voiced by the cast of Red vs. Blue, a Halo machinima.)
- Easy and Normal:

Marine(Tucker): Hey, open up!
Guard(Doc): Password please.
Marine: You gotta be kidding, what password?
Guard: The password so that we don't open to door for Brutes.
Marine: Do I sound like a Brute to you?
Guard: Well, you could be held prisoner by Brutes.
Marine: If I was held prisoner by Brutes and knew the password, then the Brutes could force me to tell you the password and open the door for them.
Guard: ... Okay, well now I'm definitely not going to open the door.
Marine: But we need ammo!
Guard: Well why don't you go ask your Brute buddies then?

- Hard:

Marine(Simmons): Hey, open up.
Guard(Grif): Password.
Marine: What?
Guard: I need the password.
Marine: You've gotta be kidding me, what password?
Guard: Password. They gave it at the staff meeting fifteen minutes ago!
Marine: Meeting? What meeting? I was out here!
Guard: Not supposed to let anyone in without it.
Marine: If the staff meeting just ended, then no one outside's gonna know the freaking password, now open up! We need ammo and the Chief is out here!
Guard: [beat]Does he know the password?
Marine: He wasn't at the meeting either!

- - Legendary:

Marine(Church): Hey, open up!
Guard(Caboose): What's the password?
Marine: Password? Oh man, I forgot...
Guard: Forgot...what?
Marine: The password.
Guard: See, that was almost right. Ah, see, the password begins with "I forgot", but ends differently. Um, try again.
Marine: No, I mean I've forgotten the password!
Guard: Nah, uh, you see, you've got it wrong again. See, you said the same thing as last time.
Marine: I'm being serious, I don't know the password!
Guard: I dunno, you changed the first part. See, tha-that part was the right part, now you've got the whole thing wrong.
Marine: No, I forgot what the password is, and I just need you to open the door!!
Guard: Alright man, now you're just guessing.

- This little exchange in the "Uplift Nature Preverse" level of ODST, between a wounded marine and the medic treating him:

Marine: No no NO!! You're not listening! It's a zoo, okay?
Medic: Well, technically it's a corporate-funded wildlife preserve.
Marine: Semantics! This whole place is one... big... cage!

Medic: Listen, marine... you're wounded... you need to try and relax...

Marine: Except us... we're the zebras! All fenced in, and ready for the slaughter!

Medic: And the Covenant?

Marine: They're the lions! RRRAAAARRRGGH!!

Medic: Careful. I think you just strained a metaphor.

Marine: (panicking) Oh God! OH GOD!! ...Is-is that serious?

Medic: Only if you keep it up...

In Reach, Kat and Six enter an upper level of Oni's Sword base while fending off Covenant.

Automated recording: Welcome to the Office of Naval Intelligence. An ONI representative will be with you shortly.
Kat: (dryly) Somehow, I doubt that very much.

A classic, from Halo 2:

Prophet of Truth: The Great Journey is nigh, and nothing, not even the Flood, can stop it.
(Master Chief teleports in, right next to a Grunt. He looks down at the Grunt)
Master Chief:: Boo.
Grunt: Aaah! (runs away, as the Chief steals his Needler)

*Headshot*
- *Pop!*
- *Confetti*
- "Yay!"
Johnson's rant at the beginning of "Outskirts" in Halo 2.

Johnson: Dear humanity! We regret being alien bastards! We regret comin' to Earth! And we most definitely regret that the Corps just blew up our raggedy-ass fleet!
Pelican Pilots: Oorah!

- The Covenant then shoot down the Chief's Pelican. As he hauls himself from the wreckage and tries to clear his head, the section title proclaims "They'll regret that too."
- And sometime later we get this exchange as a group of Marines attempt to retreat:

Johnson: Where's the rest of your platoon?
Marine 1: Wasted, Sarge.
Marine 2: And we will be too sir, if we don't get the hell out of here!
Johnson: You hit, Marine?
Marine 2: N--no sir.
Johnson: Then listen up! When I joined the Corps, we didn't have any fancy-schmancy tanks. We had sticks! Two sticks, and a rock for the whole platoon! And we had to share the rock. Buck up boy, you're one very lucky Marine.

In the October 8 2010 Bungie.net update, the first of two "Blame Stosh" clips shows three players in a Rocket Warthog, parked and shooting at an offscreen Phantom. There's a sudden, growing 'whoosh' sound, and then WAM! A Covenant drop-pod lands right smack-dab on the Warthog, triple-killing its occupants.
Before ODST came out, Bungie had a little glitch with the Brutes. Instead of them charging you while they shot at you, they would pimp walk. Naturally, this became a short-lived meme on the updates.
Anything Grunts say in Combat Evolved. Sometimes you'll walk into a room and randomly hear screams of fear, even though they don't know you're there yet. Also:
- "Leader Dead! Run away!
- "Bad Cyborg!"
- "CAN'T! RUN! WITH! THING! ON! BACK!"
- "WE'RE GONNA DIEEE!!!"
- "He flees! Thank the Nipple."
In the first game, when you've returned to the Pillar of Autumn and go through the dark vents again, just outside your exit is a battle between Covenant and Flood. But because of the narrow doorway, you can mostly only see the bullets and grenades flying back and forth, and hear the NPCs' reactions offscreen, turning an otherwise-ordinary battle into hilarity.
In Reach, Elites wielding Energy Swords are very formidable opponents. However, their simplistic AI drives them to charge directly at a player. Normally this works if the Elite can corner you. However, they fail to realize that running towards a speeding vehicle is a bad idea, even if it is a forklift.
Halo 3's IWBYD (I Would Be Your Daddy) skull is made of this. Example:

Friendly Elite" (Chief gives gun to him) One word for you. "Random Gibberish".
Brute (After someome kills another Brute):"HE WAS MY LOVER!"

Bungie made an intro video to the release of Halo featuring everyone's favorite sergeant...No no, the other one, to teach you how to survive Halo

Sergeant Johnson "BEEP them or by god they will BEEP YOU!"

Bungie PR Guy Jason Jones' (not that one) quote describing Halo 2.

Halo 2 is a lot like Halo 1, only it's Halo 1 on fire, going 130 miles per hour through a hospital zone, being chased by helicopters and ninjas ... And, the ninjas are all on fire, too.

In Halo 3, if you manage to flip over an Elephant Tank you will get the following message when you walk up to it: "Hold RB to flip... wait, what? How did you do that?"
The Legendary ending to the first game. "This is it, baby... Hold me." Johnson and an Elite hug, and the Elite grabs Johnson's butt. In Anniversary, they still hug, but Johnson grabs the Elite's butt. The Elite is briefly shocked before the Pillar of Autumn explodes.
The official strategy guide for Halo 3 has a little gem while explaining the Mauler: "firing the Mauler at someone at anything other than close range is like insulting their mother: it's just a lot of hot air and noise, and it's just going to make them angry."
In the short story "Midnight in the Heart of Midlothian", the lone surviving ODST has managed to trick the Covenant into reactivating the onboard AI, Mo Ye.

Mo Ye: Self-Destruct sequence initiated. Four minutes and counting.
The Covenant begin evacuating rapidly
Mo Ye: I'm kidding. There's no need for any countdown whatsoever.
The Elite blinked

* boom*

When Vergil unlocks the elephant. And when he (it?) has to be pushed into the Phantom's gravity lift.