The Avengers (2012)

The Wizard of Oz (1939)
There's a mention of "flying monkeys" to which Steve Rogers - a man out of time from the 1940s - exclaims "I understood that reference!"

Alien (1979)
Harry Dean Stanton repeatedly asks Bruce Banner if he an Alien, referencing the film in which he himself starred

Point Break (1991)
Tony Stark nicknames Thor "Point Break", alluding to Patrick Swayze's appearance and haircut in the film of the same name.

Reindeer Games (2000)
Iron Man calls Loki "Reindeer Games" because of his horned crown

The Lord of the Rings: The Fellowship of the Ring (2001)
As Iron Man takes Hawkeye to a rooftop, he says "Better clench up, Legolas" referencing the similarity between Hawkeye and Legolas' skill with bows and arrows.

Referenced in

Richard Roeper & the Movies: Halftime Report: The Best and Worst of 2010 (2010) (TV Episode)
Roeper says he can't wait to see this movie

Guys Choice Awards 2011 (2011) (TV Movie)
The film was mentioned

Mad: Super 80's/Captain America's Got Talent (2011) (TV Episode)
Mark Ruffalo mentions being the third actor to play the Hulk in a movie.

The Nostalgia Critic: The Avengers (2011) (TV Episode)
The Critic mistakingly thinks he's going to review this movie.

Tosh.0: Results of the Memorabilia Dump (2012) (TV Episode)
mentioned by Tosh

Atop the Fourth Wall: Bloodstrike #1 (2012) (TV Episode)
mentioned by Linkara

Mad: iChronicle/Hulk Smash (2012) (TV Episode)
Both Bruce Banner and the Hulk wanted to audition to be part of the Avengers.

General Hospital: Episode #1.12546 (2012) (TV Episode)
posters seen

The Tonight Show with Jay Leno: Episode #20.132 (2012) (TV Episode)
Jay mentions that Robert Downey Jr. from the film will be on later this week

Midnight Movie Review: The Avengers (2012) (TV Episode)
the film of this episode's topic.

The Nostalgia Critic: Alien: Resurrection (2012) (TV Episode)
Joss Whedon, who directed this movie, wrote Alien: Resurrection.

Jeopardy!: 2012 Teen Tournament Final Game 1 (2012) (TV Episode)
Title used as answer to question in Wheel of Movie Taglines category

The Tonight Show with Jay Leno: Episode #20.140 (2012) (TV Episode)
Jay says the film is the blockbuster movie of the year

The Nostalgia Chick: Men in Black (2012) (TV Episode)
Lindsay mentions seeing this movie

Hewy's Animated Movie Reviews: The Pirates! Band of Misfits (2012) (TV Episode)
Hewy says "The Pirates!" may not be in theatres for long due to this movie's release.

The Tonight Show with Jay Leno: Episode #20.151 (2012) (TV Episode)
Jay re-enacts a scene using local residents in the "Jaywalking" segment

Mad: The Iron Giant Lady/Raising a New Hope (2012) (TV Episode)
In the Mad Moments intro, it was mentioned that people went to see this movie and didn't go home till they saw all the scenes after the end credits.

Chelsea Lately: Episode #6.83 (2012) (TV Episode)
Chris mentions the movie by name.

The Tonight Show with Jay Leno: Episode #20.153 (2012) (TV Episode)
Jay mentions that Chris Hemsworth is in the film

The Tonight Show with Jay Leno: Episode #20.160 (2012) (TV Episode)
Fake list of Lindsay Lohan's excuses for her car accident includes "I forgot to take off my 3-D glasses after seeing 'The Avengers'"

Special Collector's Edition: Las amistades peligrosas (2012) (TV Episode)
release mentioned

Tosh.0: Juggalo Kid (2012) (TV Episode)
Mentioned by Tosh

Workaholics: The Lord's Force (2012) (TV Episode)
Mentioned in dialogue

Mad: This Means War Machine/iCharlie (2012) (TV Episode)
The Avengers airship appears in the This Means War Machine skit.

Conversations with Hollywood: Writing Action Movies (2012) (TV Episode)
Screenwriter Zak Penn talks about writing THE AVENGERS and the challenge of adapting super hero comic books into films.

The Tonight Show with Jay Leno: Episode #20.189 (2012) (TV Episode)
Sylvester Stallone says that the film represents a different kind of action film compared to "The Expendables 2"

Weeds: God Willing and the Creek Don't Rise (2012) (TV Episode)
mentioned in dialogue

General Hospital: Episode #1.12657 (2012) (TV Episode)
Spinelli and Ellie discuss the Avenger movie and the upcoming sequel

The Big Bang Theory: The Decoupling Fluctuation (2012) (TV Episode)
Sheldon talks about Edward Norton being replaced as the Hulk.

General Hospital: Episode #1.12662 (2012) (TV Episode)
mentioned in dialogue

The Middle: Bunny Therapy (2012) (TV Episode)
mentioned by Axl

Mad: Outtagascar/Fiends (2012) (TV Episode)
Alex mentions that the Avengers made more money than any other movie.

South Park: A Nightmare on Facetime (2012) (TV Episode)
Stan, Kyle, Cartman, and Kenny dress up as The Avengers.

Mad: FrankenWinnie/ParaMorgan (2012) (TV Episode)
A Halloween party being held at Stark's New York skyscrapper.

Saturday Night Live: Louis C.K./Fun (2012) (TV Episode)
Referenced in the "Hotel 55" segment

Mad: Total Recall Me Maybe/The Asgardigans (2012) (TV Episode)
A picture of the Ruffalo Hulk appears on the side of a building in the Spy Vs. Spy skit.

Glee: Dynamic Duets (2012) (TV Episode)
mentioned by Finn

Mad: Here Comes the Doom/Brain Purge (2012) (TV Episode)
Mark Ruffalo Hulk appears in the Ask a Celebrity skit.

Last Man Standing: Mother Fracker (2012) (TV Episode)
Mandy mentions Mark Ruffalo and The Hulk

The Tonight Show with Jay Leno: Episode #21.62 (2012) (TV Episode)
JibJab recap of the year depicts the Avengers saying "We really kicked box office butt"

Special Collector's Edition: Especial Navideño (Top Películas Navideñas) (2012) (TV Episode)
poster shown

Portlandia: Squiggleman (2013) (TV Episode)
Title mentioned

Mad: The Perks of Being a Wallcrawler/Regular Shogun Warriors (2013) (TV Episode)
A skit that involves Hawkeye using other weapons besides a bow against Loki's army.

The Big Bang Theory: The Cooper/Kripke Inversion (2013) (TV Episode)
Leonard says, "Sometimes there's a secret ending, like in 'The Avengers.'"

The Nostalgia Critic: Son of the Mask (2013) (TV Episode)
"...who's almost as silly looking as the Avengers' Loki, but not quite."

Iron Man 3 (2013)
The dialog between Tony Stark & his kid friend involves the mention.

Community: Heroic Origins (2013) (TV Episode)
Abed says, "You linked all of our stories, like how the cosmic cube assembled the Avengers."

Features

Galaga (1981) (Video Game)
A computer technician is seen playing this video game.

Thor (2011)
Thor's battle with the Destroyer is included in Stark's briefing.

Captain America: The First Avenger (2011)
Steve Rogers has a flashback of when he fought HYDRA in World War II.

Featured in

Captain America: The First Avenger (2011)
Clips from the upcoming movie are shown after the credits.

The Blockbuster Buster: ERod Reacts to The Avengers Trailer (2012) (TV Episode)
trailer is reviewed

CineMaverick TV: Episode #1.1 (2012) (TV Episode)
trailer shown

Projector: Marvel's The Avengers (2012) (TV Episode)
Film Brain gives a spoiler-free review of the film

The Tonight Show with Jay Leno: Episode #20.134 (2012) (TV Episode)
Scarlett Johansson introduces a clip from her film

The Tonight Show with Jay Leno: Episode #20.135 (2012) (TV Episode)
Robert Downey Jr. introduces a clip from his film, and altered clip of trailer incorporating "tanning mom" as villain Fake Bake

Maltin on Movies: The Avengers Special (2012) (TV Episode)
Movie reviewed in this episode.

Bum Reviews: The Avengers (2012) (TV Episode)
movie is reviewed

Half in the Bag: The Avengers and CPHPIX Film Festival (2012) (TV Episode)
movie is reviewed

The Nostalgia Critic: Alien: Resurrection (2012) (TV Episode)
mentioned among anticipated blockbusters

The Big Review: Episode #1.4 (2012) (TV Episode)
The movie was reviewed and the trailer was shown.

The Tonight Show with Jay Leno: Episode #20.186 (2012) (TV Episode)
Clip shown in montage of Jeremy Renner films

Maltin on Movies: Trouble with the Curve (2012) (TV Episode)
Movie reviewed in this episode.

That Sci-Fi Guy: 2012: Zombie Apocalypse (2012) (TV Episode)
suggests a zombie was hit with one of Hawkeye's arrows

Atop the Fourth Wall: The Incredible Hulk #1 (2012) (TV Episode)
recalling the most recent Hulk adaptation

Great Movie Mistakes IV (2012) (TV Movie)
Clips of mistakes shown

Bad Movie Beatdown: Review of 2012 (2013) (TV Episode)
says is one of the best films of 2012

The Blockbuster Buster: Honest Review: The Avengers (2013) (TV Episode)
movie is reviewed

The 85th Oscars (2013) (TV Special)
Nomination presentation for best visual effects.

The Nostalgia Critic: What's with the Princess Hate? (2013) (TV Episode)
recalling Black Widow as a strong, independent female

Iron Man 3 (2013)
Tony Stark has a flashback to when he was almost trapped in the wormhole and a clip is shown.

The Tonight Show with Jay Leno: Episode #21.139 (2013) (TV Episode)
a clip is shown in a montage of Chris Evans films

The Nostalgia Critic: Why Is Loki So Hot? (2013) (TV Episode)
Loki and his hotness are the subject of this editorial

Spoofed in

The Tonight Show with Jay Leno: Episode #20.100 (2012) (TV Episode)
Trailer for a fake Chinese bootleg of the film is shown

The Bitter Advice (2012) (Short)
After the credits the cast and crew mock the Shawarma scene in The Avengers.

The Reunion (2012)
The four lead characters wear The Avengers outfit (Hulk, Thor, Captain America, and Iron Man) in the stag party. In the final scene at the airport, the character, still in the Avengers outfits, spoofed the Marvel heroes.

Mad: Average-ers/Legend of Dora (2012) (TV Episode)
The Average'ers skit is a spoof of this movie.

Saturday Night Live: Jeremy Renner/Maroon 5 (2012) (TV Episode)
Spoofed in the Avengers segment

30 Nights of Paranormal Activity with the Devil Inside the Girl with the Dragon Tattoo (2013)
Characters and scenes are spoofed

Robot Chicken: Robot Fight Accident (2013) (TV Episode)
musical version

The Simpsons: Dark Knight Court (2013) (TV Episode)
"The Dependables" parody

The Starving Games (2013)
Characters from this movie are portrayed.