Perplex City is a long-term alternate reality game (ARG) presented by Mind Candy, a London-based development team. The first "season" of the game had players looking for "The Receda Cube" (referred to simply as "The Cube"), a priceless scientific and spiritual artifact to the people of a fictional metropolis known as "Perplex City", that had been stolen and buried somewhere on Earth. The game offered a real-life £100,000 reward (approx. $200,000 or €150,000) to whoever found it. Like most alternate reality games, the story of Perplex City is told through blogs, puzzles, and other various media.

The game began in April 2005, and was won by Andy Darley of Middlesex, UK, who found The Cube in a wood in Northamptonshire, UK on 2 February 2007. blank">Digital Treasure Hunt gets Winner, a BBC story.

According to _Mind Candy, the first wave of cards for the new game season, called Perplex City Stories would be released on March 1 2007. However, in June 2007, they released an announcement which declared that the second season was on indefinite hold.