Perplex City

An Alternate Reality Game, Perplex City is a cross-media experience, played
partly through each of: the web, downloadable puzzle games, newspapers, boxed
products, emails, online forums, and many other media. The overarching game is
in a murder/mystery style: to solve the mystery of who stole the Receda Cube,
and to work out where on Earth it is now, with a $200,000 prize going to
whoever finds it.

Being multi-media in the literal sense (i.e. lots of different media, not just
“graphics and sound” as that term now means), each used both independently (as
stand-alone experiences) and cooperatively (multiple media needing to be used
simultaneously in different ways) to advance the story and allow players to
play the game, it is hard to pin down into one particular genre. The bulk of
the ARG is played across hundreds of proprietary websites each presented as
“real”, deliberately crafted to be indistinguishable from real-life websites
and bona fide companies, bar hints such as the textual content of a site.