Approval of God: Over the years, countless targets of parody have sent letters and photographs to MAD showing their approval over being the target of a parody.
Banned in China: One page containing a strip mocking the British royal family had to be ripped from 25,000 copies manually before that issue could be sold in the UK. Though they have relaxed their attitude on such jokes since then.
Creator Backlash: Mort Drucker illustrated the 24 parody that ran in issue #429. The original intent was to have his art colorized digitally, but when he was dissatisfied with the results, it was redone with a grayscale shading instead. He didn't like this either, and there was no time for him to try shading it himself, so he took his name off the art and it was credited to "Bob Julian".
Creator Couple: A few spousal teams have contributed over the years, including George Woodbridge's wife, Deborah Mills Woodbridge, and Dick DeBartolo's husband, Dennis Wunderlin.
Executive Meddling: Mike Snider revealed in his now-defunct blog that his first approved piece for the magazine, a parody of "A More Humane Mikado", was greatly altered by the editors, who felt that The Mikado would be too unfamiliar to readers. As a result, the parody barely scanned to the song at all.
Follow the Leader: The magazine's success inspired a succession of copycats, including Cracked and countless others, many of which even had Expys of Alfred E. Neuman as their mascots (and many of which lasted for only a few issues). William Gaines supposedly kept a voodoo doll that had pins marked with the names of Mad knockoffs; by his death in 1992, only the Cracked pin remained.
Gaines even launched his own rip-off, Panic.
Life Imitates Art: The Wheel of Fortune parody ends with the contestant owing a large amount of taxes due to all the undesirable prizes he's accumulated. Not long after the parody was published, the show dropped the "shopping" aspect for this very reason.
Missing Episode: The original cover art for issue #300 featured George H. W. Bush burning a flag with Alfred's face on it. The cover was determined to be in poor taste, so it was hastily replaced with a stock image of Alfred.
Old Shame: MAD lent its name to an Animal House-style comedy, Up the Academy. After it did poorly at the box office, MAD was quick to disown it, and wrote a two-page satire of their own movie, which ended with the entire staff fictitiously quitting in shame. William M. Gaines also paid Warner Bros. $30,000 to remove every reference to MAD from the movie. However, following being more integrated in the Time-Warner corporate culture after Gaines's death, (as compared to their relative freedom under Gaines during the Warner Communications/early Time Warner years), the references were restored on all recent TV airings and the DVD. Despite this, it's still Old Shame to the MAD staff.
Some characters in parodies refer to their previous roles as such. In the parody of "Eraser", Arnold's character is asked to "erase" some of his co-stars' previous roles, and he tells them to wait until he's done with his own.
Frank Kelly Freas, who did the majority of the early magazine covers, left in 1962. After his departure, the main cover duties went to Norman Mingo until 1980, Jack Rickard until his 1983 death, and then Richard Williams for most of the mid 1980s-early 1990s. By the end of the decade, cover duties were rotated among several different artists until about 2003, when Mark Fredrickson became the primary artist (although he had done the occasional cover as early as 1995). Interestingly, the Burbank reboot seems to be going back to having rotating cover artists, as each of the first six issues was illustrated by a different artist.
After Antonio Prohías retired in 1986, Spy vs. Spy went to other artists. Bob Clarke did the art from 1987 to 1993, then Dave Manak until 1997 (except for two installments early in Manak's tenure that were drawn by George Woodbridge instead), and Peter Kuper ever since. Gag writing during the other artists' timespan was typically handled by Duck Edwing, although a few other writers pitched in now and then. Ever since Kuper took over, he has handled almost all of the gag writing as well.
This has also shown up in Monroe and..., which was originally drawn by Bill Wray (the same one who worked on The Ren & Stimpy Show in the 1990s). After a short retirement, the feature was briefly revived with Tom Fowler as the artist before retiring again. The change in artists was supposedly because Wray (who, like most of the staff, has plenty of work outside the magazine) had very little time to draw and color the strip on time, meaning that he had to do a rush job.
Mike Snider's "Celeberity Cause-of-Death Betting Odds" was originally drawn by Thomas Fluharty for seven of its first eight installments (the seventh, in #364, was done by James Warhola instead). Hermann Mejía then drew it for the rest of the run, except for issues #370 (Warhola again), #375 (Fluharty again), and #398-#401 (Jon Weiman). The feature was retired with #417, made a one-time return with #423, then was revived starting at #455 with "Jack Syracuse" (read: Sam Viviano) as the artist. After Snider quit the magazine in the mid-2000s, the series has been uncredited.
Also present in the Star Wars parodies of the first six movies. Dick DeBartolo and Nick Meglin co-wrote the A New Hope parody, with Harry North as the artist; the next four had just DeBartolo writing and Mort Drucker drawing. Revenge of the Sith switched to David Shayne for the writing and Hermann Mejía for the art, and The Force Awakens parody was drawn by Tom Richmond (except for some Call-Back panels from the A New Hope parody) and written by "David Richards" (a pseudonym for an existing writer).
Outlived Its Creator: Bill Gaines died in 1992, but the magazine is still in business. (He's still credited as the "founder" among "The Usual Gang of Idiots".) Also, Spy vs. Spy creator Antonio Prohías retired in 1987 and died in 1998, but his strip still appears in the magazine.
Basil Wolverton appeared very sporadically in the publication, just 9 issues from 1954 to 1970. In spite of that, he's regarded as one of the top artists for the magazine, being dubbed "The Michelangelo of MAD Magazine" by The New York Times. MAD XL, a separate magazine reprinting older articles from the main publication, even named him an "Idiot of the Issue" in 2004.
Many of the other iconic artists in the early years did not stay for long either. Most notably, Will Elder and Harvey Kurtzman were the main artist/writer duo in the early comic-book days, but both men left in 1958 (although they returned briefly from 1984-88). Other defining contributor who didn't stick around for long included John Severin (who quit after issue #10 and later became the flagship artist of rival Cracked) and Frank Kelly Freas (who primarily did cover art in the early days, but did not contribute at all after 1962). To be fair, all of them are known for something other than just their MAD work.
Technology Marches On: In their article "The 50 Worst Things About the Internet", one of the captions showed a family huddled around their tiny computer monitor watching a movie on Netflix, while their big beautiful flatscreen TV sat in the living room unused. The issue came out in 2009; nowadays there are multiple ways to stream video sites through your television (even back then, the family could have plugged the computer into the TV with an HDMI cable if they really wanted to). Hell, many TV's now have wifi connectivity, eliminating the need for a middleman altogether.
Issue #122 (October 1968) features Alfred holding a pin and several balloons with caricatures of prominent politicians of the day. The original cover art featured a caricature of Robert F. Kennedy. As RFK was assassinated just before the issue's publication, his caricature was hastily replaced with one of Alfred.
Issue #411 (November 2001) was originally supposed to have a cover featuring Alfred mistaking crime scene tape for the finish line of a race. The cover was deemed insensitive after 9/11, so it was hastily pulled and replaced with a stock Alfred image photoshopped to have an American flag in place of his missing tooth. A few copies of the original cover supposedly got out, though.
According to this interview with Fold-In artist Al Jaffee, he created a Fold-In themed to the 2012 theater shooting in Aurora, Colorado, and the editors decided that it was in poor taste, and 600,000 copies were shredded to cover it up. The Fold-In was finally approved for use in issue #7 of the reboot.
Writer Revolt: A running joke in the magazine, and somewhat true behind-the-scenes occasionally.
Write What You Know: Dick DeBartolo was working for Mark Goodson Productions when he was tapped to write the Family Feud parody. Naturally, he took that opportunity to knock down every trope that show presented (and submitted the parody under a pen name).
You Look Familiar: Certain contributors have returned after a long gap. Most notably, Will Elder and Harvey Kurtzman returned to illustrate some articles in The '80s, and artist Joe Orlando, a semi-regular between 1957-1969, returned for four articles in 1997.
A skit from the Cartoon Network series had a scientist claiming dinosaurs didn't roar because "they are part of the bird family". While the classification is utterly mixed up (birds are part of the dinosaur family, not the other way around), it has lately been discovered that dinosaurs really didn't roar like they how they are always portrayed since their vocalizations were more like those of crocodiles.
Acting for Two: Kevin Schnick and Rachel Ramas voice a large percentage of the show's characters - and it's pretty obvious.
Development Hell: MAD has not been renewed for a fifth season despite Cartoon Network not officially declaring the show's cancellation. Since the show is off Cartoon Network's schedule as of 2015 and Cartoon Network is focusing on other shows (some of which are Lighter and Softer), it seems as if it's gone for good.
Lightning McQueen is voiced by Owen Wilson in the original movies, but any spin-off media such as the Car Toons will have him be voiced by Keith Ferguson instead, who would also occasionally reprise his role in this series.