{{Alternate Reality Game}}s began (approximately) with the game concocted to promote the movie ''Film/AIArtificialIntelligence'', affectionately known as ''The Beast''. Alternate Reality Games make use of a variety of different media, and therefore combine tropes from different media, while inventing some of their own.

AlternateRealityGameTropes include:
* AlternateRealityGame
* EntryPoint
* {{Flashmob}}
* {{Puppetmaster}}

Notable stand-alone [=ARGs=] include:
* WebVideo/EverymanHYBRID
* ''TabletopGame/PerplexCity''
* ''Majestic''
* WebVideo/MarbleHornets
* ARG/TheHuntForTheGangadiddle
* WebVideo/BenDrowned
* {{VideoGame/Ingress}}

The following series have alternate reality games tied in to them:
* ''Series/{{Heroes}}'': The Heroes 360 experience, where the participants take cues from the character Wireless to solve the mystery of Primatech paper.
* ''Series/{{Skins}}'': A BritishSeries with tie-in blogs and videos, complete with puzzles to find out about some characters.
* ''ARG/TheLostExperience'' is a vast and complicated ARG for ''{{Series/Lost}}'', which often makes a lot more sense than the programme itself.
** Another ARG was launched before season 4 called "Find 815." Another one launched at Comic-Con 2008 called the "Dharma Initiative Recruiting Project". Both of these were closer to simple online stories with minigames included than true [=ARGs=], and the latter was so plagued with delays and had so little apparent purpose that it was aborted before the end.
* ''ARG/ILoveBees'' established a backstory for the game ''VideoGame/{{Halo 2}}'' (involving a time-traveling AI from the game's era trapped in a [[http://ilovebees.com present-day homemade website about beekeeping]]), made by the same people who ran The Beast. Players helped repair the fragmented AI and get it home, while unlocking audio clips that told a backstory about the day of the Covenant invasion.
* ''ARG/HuntTheTruth'' was a later campaign for ''VideoGame/Halo5Guardians'', centering on a journalist (played by Key of ''Series/KeyAndPeele'') searching for the truth about the Master Chief's origins.
* ''VideoGame/{{Halo 3}}'' also had one ("Iris"), but due to changes in advertising laws, it had Bungie and Xbox 360 logos slapped all over it right from the start, much of it took place on Halo.com and Microsoft.com, and it ended abruptly with a "buy the game for the rest!" cliffhanger.
* The 2007 ''Film/{{Transformers}}'' movie has the [[http://www.tfwiki.info/wiki/Sector_Seven_%28game%29 Sector 7]] AlternateRealityGame. It [[strike: reveals to anyone who'll listen]] has as its main plot that the franchise is a cover-up for ''real'' alien robots. [[MilkmanConspiracy Japanese toy company Takara was the first to be brought in.]]
* ''Film/JohnDiesAtTheEnd''
* One might say the earliest [=ARG=]s were the secret decoder rings delivered to fans of certain radio shows (as immortalized in ''Film/AChristmasStory'')... after all, at their root, it's a puzzle to be solved that leads inevitably to ProductPlacement.
* VideoGame/{{Portal}} also has one.
* ProjectLegacy is an VideoGame/AssassinsCreedI ARG.
* 42 Entertainment, founded by the team responsible for The Beast, is responsible for many tie-in [=ARGs=]; in addition to the aforementioned ''ARG/ILoveBees'', they have also made:
** Year Zero, based on the Music/NineInchNails ConceptAlbum of the same name, explores the album's premise of the war on terror turning the United States into a totalitarian Christian theocracy which enforces its power through fear of terrorism, kidnapping dissidents and [[GovernmentDrugEnforcement drugging the water supply to keep the public obedient]].
** Why So Serious, which promoted ''Film/TheDarkKnight'', acts as a bridge between it and ''Film/BatmanBegins'', telling the story of Harvey Dent's campaign for Gotham District Attorney and the Joker's rise to power in the city's criminal underworld.
* ''Series/{{Torchwood}}'' has an ARG set during the second season revolving around an alien DNA invasion, with several original websites created just for the game.