No Intelligent Life Here

Pray that there's intelligent life somewhere up in space,

'Cause there's bugger all down here on Earth.

—Mr. Pink, Monty Python's The Meaning of Life

Peter: [leaning on a rock] Do you think it's possible that someone out there has intelligence greater than my own?
Curls: Sure.
Peter: Where?

Curls: You're leaning on it.

—BC

A Stock Joke that usually goes something like this:

Alice: "Did you hear that scientists are looking for intelligent life on other planets?"
Bob: "I guess they gave up on finding any on this planet!"

Or in other cases:

Alien agent/scientist: "I came to this planet many years ago to investigate the rumors about existence of intelligent life, and I can safely say that they have been thoroughly disproved."

Examples of No Intelligent Life Here include:

Film

The aforementioned "The Galaxy Song" from Monty Python's The Meaning of Life.
The beginning of Muppets In Space, as well as a trailer joke there.
- The joke used in the film proper was a Statler and Waldorf quip about how they don't have lives on earth (as in social lives).

Literature

A chapter of Carl Sagan's book Pale Blue Dot is titled "Is There Intelligent Life On Earth?" and covers a fictional alien visitor observing things from space that cause it to ask that question.
Used near the end of the novel George's Cosmic Treasure Hunt: "And through the portal they could see one of the most beautiful planets in the whole galaxy, where there is warmth, and light, and water. Where there is life. Some of it, possibly, intelligent."

Newspaper Comics

The comic strip Ziggy: "We're looking for intelligent life. If you find any, call this number."
Calvin and Hobbes (Scientific Progress Goes "Boink", page 29):

Calvin: Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

- Recycled by Shoe.
Used in Mafalda, when she and her friend Felipe eagerly await the radio news on the latest space flight to Mars, Felipe comments excited on how amazing it is that there may be life on other planets. When the radio instead only gives news on the Vietnam war and other conflicts, Mafalda says that the amazing thing is that there is life on this planet.

Live Action TV

In the Frasier episode The Candidate, Frasier and Niles were both promoting a political candidate who they learn believes he was abducted by aliens. When they discuss whether they can keep supporting him in light of this there is this exchange:

Niles: Answer me this: can you tell me with any certainty that in such a vast universe there isn't intelligent life on other planets?
Frasier: (glares) At the moment, I'm not sure there's intelligent life in this kitchen!

On Home Improvement, Brad and Randy are trading insults and Randy says that Brad would fit in on Mars where there's no sign of intelligent life. Tim scolds them with "First of all... they've never confirmed that."

Video Games

In a Have a Nice Death sequence from Space Quest V, two aliens watch Roger go down in flames over their planet (because he was Too Dumb to Live, the game suggests):

Crumpella: I wish we would discover someone else out there among the stars...
Slep: Don't be silly, Crumpella! Everyone knows there's no intelligent life out there!

Webcomics

Used with alternate dimentions instead of space in the General Protection Fault/Kevin and Kell crossover, when Ki and Nick are visiting Kevin & Kell's world - filled with Talking Animals of every size and shape - but no humans. Leading to this exchange...

Lindesfarne: So in your world, there's only ONE intelligent species?
Ki: Yeah, Dolphins. Just kidding... but sometimes I think the jury's still out on us humans.
Lindesfarne: But surely, with no significant differences to drive you apart, you must all live in peace and harmony!
Ki: ...

In The Inexplicable Adventures of Bob, the alien Nemesites have held the lease to our planet for eons, designating it as a nature preserve, and consider the young species of humanity to be unintelligent wildlife. Princess Voluptua is deeply concerned about whether changing that legal designation to grant humans Imperial Citizenship would do mankind more harm than good.
In a strip-slay of Poorly Drawn Lines from a security expert who took a closer look at how Symantec/Norton antivirus software works: behold.

Western Animation

Johnny Bravo had this in one episode as an Expy of Kirk said that there was no intelligent life there while in the middle of a park right before the title character ended up switching places with him in a beam up on a parody of Star Trek.
Lilo and Stitch: Upon discovering that the titular alien has landed on an isolated island - Hawaii;

Grand Councilwoman: Can we not simply destroy the island?
Pleakley: NO, crazyhead! The mosquito's food of choice, primitive humanoid lifeforms, have colonies all over that planet.
Grand Councilwoman: Are they intelligent?
Pleakley: No. But they're very delicate. In fact, every time an asteroid strikes their planet, they have to begin life all over. Fascinating, isn't it?

Buzz Lightyear's introduction in Toy Story could be read as a more subtle version of this. Immediately prior to meeting the other toys, Buzz, thinking he's a real space ranger, describes the "planet" (actually Andy's bedroom) that he finds himself in: "There seems to be no sign of intelligent life anywhere."
In one episode of Garfield and Friends, an alien, having observed the antics of the farm's residents (it was in the U.S. Acres segment), reports that the mission to find intelligent life has failed.

Other

Kent Hovind used this joke in one of his "lectures". Given that Mr. Hovind is a young Earth creationist whose views are often considered spurious even by other young Earth creationists, one may wonder if this actually helps to confirm or refute the trope.
On a T-shirt: "Beam me up, Scotty! There's no intelligent life down here!"
- Also on a pin (a yellow pin, to be specific).
The tongue-in-cheek Search for Terrestrial Intelligence project from the 90s is still looking.