The Dreamhouse's address is 1959 Malibu Way. The address is the date Barbie was established and Malibu is likely reference to another popular Barbie released in the 70's.
Ken's Goofy Print Underwear has his name written on it, in several of the fonts used on Ken dolls' boxes and ads over the years.
The opening of "A Smidge of Midge" took inspiration from the commercial for the first Midge doll, which began with Barbie answering the Dreamhouse doorbell to find her friend making a surprise visit.
"Ken-Tastic, Hair-Tastic" begins with Barbie singing, "Get Your Sparkle On" while showering.
Raquelle accidentally refers to Chelsea as "Kelly", a shout out to the original name that character had in The '90s and the Turn of the Millennium before being rebranded/renamed.
After meeting Grace, Barbie proclaims, "She is so in style!", name-dropping the doll line that introduced Grace.
Other Outside References
As mentioned on the main trope page, Raquelle's slow-motion run in "A Day at the Beach" has music evoking that played during the opening of Chariots of Fire.
"Closet Princess 2.0" borrows heavily from 2001: A Space Odyssey, most notably through Barbie having a Cyber Cyclops that refuses to let her go outside, as well as a topiary of cavemen beating a monolith.
"Occupational Hazards" also features music similar to "Also sprach Zarathustra" and a close-up of Ken's head in a space helmet while flashing lights fly by.
Mega Neko Blissa's entrance in "The Shrinkerator" calls to mind Jurassic Park, with Bad Vibrations in a water dish, and Blissa roaring like a T-rex.
A He-Man action figure can be seen in Chelsea's dollhouse.
It shows up again in "Happy Bathday to You", sitting in a pile of Chelsea's toys.
Princess Beatrice's infamous hat from the Royal Wedding can be seen being dragged out of Barbie's house in "Closet Clothes Out".
Raquelle quotes Jaws in "Accidentally on Porpoise" to explain her fear of dolphins.
In "Mission Impawsible," Blissa, Taffy and Tawny see a film called Paws, where the shark is replaced with a giant Blissa. Taffy and Tawny are terrified, but Blissa comments "Meh, I've seen worse. I'vedoneworse."
Part one of "Gone Glitter Gone" has Stacie hiss, "Chelsea, give us the precious!" in a manner similar to Gollum from The Lord of the Rings.
Part two of "Gone Glitter Gone" evokes The Godfather as Chelsea implores Skipper, "Make me an offer I can't refuse." Also, Skipper gives Chelsea the severed head of a plush horse, offering to trade the whole horse for the glitter jar.
Songs promoted in "Ryan's Greatest Hits" include "What a Ryan Wants", "Your Ryan is a Wonderland"note John Mayer doesn't have a page here as of this writing., "Ice Ice Ryan", "Oops, I Ryaned Again", and "I Kissed a Ryan", complete with pictures of Ryan posing like each of those linked singers.
The announcer claims that any unsold CDs will get stashed into "the vault".
One of Ryan's Imagine Spots in "Playing Heart to Get" borrows Forrest Gump's expression, "Life's like a box of chocolates."
Ken quotes Spider-Man when he describes his Barbie Sense in "Occupational Hazards", claiming, "With great power comes great responsibility."
Summer rides the Mattel-branded hoverboard from the Back to the Future sequels at the end of "Endless Summer". This shows up again in "Malibu's Empirical Emporium".note Mattel has actually sold their own branded prop replica of the board, which is likely why they were able to use it in these episodes.
"Another Day at the Beach" opens on a sand sculpture of the Rock 'Em Sock 'Em Robots.
The entire ending of "Happy Bathday to You" parodies the famous ending scene of Thelma & Louise.
Raquelle cries I'm Melting!! when Ken sprays her with a hose at the end of "Cringing in the Rain".
The TV Special episode "Trapped in the Dreamhouse" reveals that the Dreamhouse has a Raiders of the Lost Ark-styled booby trap as well as a staff-and-gem-using locator and a thermal exhaust port weakspot. In addition, when Barbie has to take things out of her handbag so that it'll be the same weight as the thing she wants to remove from the booby trap, one of the things she takes out is a standard lamp.
