The title pretty much says it all. They can be intentionally humorous, or otherwise. Here are mine:
On Star Trek: Voyager, when Harry Kim is working with Seven of Nine for the first time, he’s trying to make small talk and says, “The Borg must meet lots of people, huh?” The death glare she gives him is one for the ages.
Once on Power Rangers, someone tells the Rangers they must face the Pine-Octopus, “a monster with all the powers of a pineapple and an octopus.” (I almost fell off my chair.)
One of my favorite lines on House:
<House’s three ducklings come into his office>
DUCKLING: We’ve got anal leakage!
HOUSE: What, all of you?
In the monster movie, The Host, there’s a scene where a grief-stricken family mourn a child they believe to be dead. Their reactions are so over the top I wanted to laugh, but I thought it would be insensitive because, y’know, dead kid. Then the reaction levels continued to escalate until I couldn’t help but laugh out loud.
From Silverado:
Hobart: Baxter! Hawley! Where the hell’ve you been? You’re late and I tell you, I don’t like it. It’s a bad start, boys. I got my people down there throwin’ snowballs and rarin’ to go.
Emmett: I’m afraid it is a bad start, friend, 'cause my name ain’t Baxter, he ain’t Hawley.
Hobart: You’re not Baxter?
Emmett: Name’s Emmett.
Hobart: You’re not Baxter either?
Paden: No, I’m not Hawley.
The mostly forgettable killer-zombie movie Night of the Creeps contains the following memorable lines:
LAW OFFICER (to a room full of sorority girls): I got good news and bad news, girls. The good news is your dates are here.
SORORITY GIRL: What’s the bad news?
OFFICER: They’re dead.
Supernatural has excellent comedy episodes amongst the angst. Tall Tales, Changing Channels, Mystery Spot, The French Mistake etc. Laughed A LOT at the opening for Changing Cannels in particular, but they were all good. “Too precious for this world” - ha!
Big Love had a few moments that made me laugh out loud. One was when Nicki was scolding Bill about his “animal urges” concerning Margie.
The Wire when Herc is playing the theme from Shaft.
Rossi telling a local cop that Reid was “left in a basket in front of the FBI.”
In one episode of ER, a nurse is about to give a patient a shot. For some reason the patient’s genitals are exposed.
Nurse (warning him about the needle): “Little prick.”
Patient: “Hey, it’s cold in here.”
At least in the modern era of television, it would be more remarkable for a non-comedy show NOT to have some truly hilarious moments. The Wire, Breaking Bad, Deadwood, Rome, Game of Thrones… all have too many laugh out loud moments to even begin listing.
From Law & Order (original recipe); Lennie and Ed (I think) are at the coroner’s office to get some information about an autopsy. Dr. Rodgers is busy and doesn’t have much time for them:
Rodgers: I got another body coming in. Guy took a javelin to the chest.
Briscoe: Why are you still in this line of work?
Rodgers: Free javelins.
Chin telling Kono: “His trunk is bigger than your apartment.”
The West Wing scene when six foot tall Allison Janney says to 4’11" Kristin Chenoweth “I can’t believe we’re the same species.”
It’s the visual that makes it work.
From yesterday’s episode of Doctor Who:
The Doctor: I need to borrow your horse.
Preacher: His name’s Joshua. That’s from the Bible.
The Doctor: No it isn’t.
Preacher: Excuse me?
The Doctor: I speak horse. His name’s Susan. And he wants you to respect his lifestyle choice.
In Parenthood, there was a poetry reading given by Mike O’Malley.
He writes this poem about Sarah, who is there with her daughter. The poem is like ‘the flower opens, spraying the world with it’s love…’ or something. There’s this one moment when Sarah looks at her daughter, saying ‘it’s totally about flowers, right?’ Daughter responds, ‘no, I think it’s about your vagoozle!’
The Jose Chung’s From Outer Space episode of the X-Files was full of them, but my favorite was “You don’t play dungeons and dragons for as many years as I have without learning a little something about courage.”
One of my favourite lines from the film! 
Two scenes in Dawn Of The Dead that cracked me up:
From The X-Files episode where an insurance salesman knows how people will die:
Insurance salesman: You know, there are worse ways to go, but I can’t think of a more undignified way than autoerotic asphyxiation.
Fox Mulder: Why are you telling me that?
Thought of another:
Star Trek: Voyager.
Doctor: You’re a woman, Seven!
Seven of Nine: Is that an observation or a diagnosis?
