* ActorAllusion: In 3.5 ''Application'd'', Zaboo can be seen wearing a [[http://www.effinfunny.com/legend-store?id=1 ''Legend of Neil'' shirt]]. ''TheLegendOfNeil'' is another web series, created by Zaboo's actor, Sandeep Parikh. There are at least two [[WebVideo/DoctorHorriblesSingAlongBlog Dr. Horrible]] references: Riley calling Zaboo "Bad Horse," and Codex putting up her fists while referring to "hammers." Also, Codex owns a frozen yogurt maker; in the musical, froyo was an important symbol for Penny and Billy's relationship.
* ActingForTwo: Tink's twin sisters Tara and Lara were originally supposed to be played by twin actresses but due to a scheduling snafu, they had to hire one of the extras to play both parts. And she had no acting experience.
* HeyItsThatGuy!: Considering what a shoestring the series started on, the number of these it's wracked over the years is doubley impressive.
** Creator/WilWheaton plays Fawkes, leader of the Axis of Anarchy.
** The 2009 holiday sketches featured [[Series/{{Heroes}} James Kyson Lee]] and [[UglyBetty David]] [[Series/StargateUniverse Blue]].
** The end of season four has [[TheBigBangTheory Simon]] [[WebVideo/DoctorHorriblesSingalongBlog "Moist"]] [[TheBigBangTheory Helberg]] making a cameo as one of the Game Masters.
** Season 5 has more than everything else thus far put together.
*** [[Series/BuckRogersInTheTwentyFifthCentury Erin Gray]], unique for not [[TheCameo cameoing]] or AdamWesting as most of the below are, but as a NoCelebritiesWereHarmed version of Creator/ElisabethSladen.
*** [[Series/BattlestarGalacticaClassic Richard]] [[Series/BattlestarGalacticaReimagined Hatch]] also showed up.
*** Tony [[TheLegendOfNeil "Neil"]] Janning as the panel doorman that shoos away Zaboo
*** Tay Zonday of Chocolate Rain fame as himself
*** [[Series/StarTrekTheNextGeneration Brent Spiner]] and [[Series/MythBusters Grant Imahara]] as themselves.
*** NathanFillion!
*** Episode 7. [[NeilGaiman Neil Freaking Gaiman]]. That is all.
*** Episode 8 [[HerculesTheLegendaryJourneys Kevin]] [[Series/{{Andromeda}} Sorbo]], and an entire party's worth of people you vaguely recognise, including [[{{Chuck}} Zachary Levi]], [[Series/BuffyTheVampireSlayer Tom Lenk]], [[{{Eureka}} Colin Ferguson]], [[{{Dollhouse}} Dichen Lachman]], and ElizaDushku.
*** Episode 11. Wait a minute, is [[StanLee that...]] okay, now they're just showing off.
*** One gets the impression that they managed to get all those celebrities by giving them a chance to meet all the other celebrities.
* OneOfUs:
** FeliciaDay definitely knows what she's writing about. Even people who don't play games but spend a lot of time online will recognize the character types.
** And do we even need to talk about Creator/WilWheaton and his massive geekitude?
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