Perplex City

And Gyvann said, "Doubt not that the Cube speaks or that its voice is heard."

—text translated from the green leitmark

Perplex City is an Alternate Reality Game by Mind Candy which ran for over two years starting in April 2005. The titular metropolis exists in another dimension with connections to Earth and has slightly better technology and a society based around puzzles. One of their major artifacts, the Receda Cube, was stolen and hidden somewhere on Earth. Lacking the ability to send people to retrieve it, the citizens of the Perplex City Academy formed a team to recruit people from Earth to find and return the Cube.

Perplex City may be the ARG which has appeared in the most forms of media during its run. The primary connection between the city and Earth was via puzzle cards, which were sold in randomized packs. The cards had clues hidden on them, as well as a code to enter online to earn points for solving the actual puzzle. There was also the obligatory website, which had (in addition to basic information) a number of hidden URLs and live online events. The game also appeared in newspapers, on television and radio, on multiple telephone lines for players to call, at a live concert and on a music CD.

The prize for finding the cube was £100,000, awarded to a player in February 2007. Additionally, players could earn leitmarks (which took the form of small rubber pins and icons on a player's profile) for solving a certain number of cards or for other achievements.

A second season, which was to involve players assisting one of the characters solve a murder mystery, was repeatedly delayed, and then cancelled when much of the development staff resigned. Perplex City was repurposed as a general puzzle-solving Web site, We Love Puzzles, and Mind Candy is, at the time of this writing, selling cell phone charms with an MMORPG attached.

Tropes used in Perplex City include:

Aborted Arc (season 2/Violet Underground)
All There in the Manual (As to be expected, you had to go over a horde of different media to get the whole story, some of which wasn't revealed until after the first season ended.)
Alphabet Soup Cans (both on the cards and in-story)
Alternate Reality Game
Block Puzzle (Serious Scientific Sokoban)
Bribing Your Way to Victory (At least one leitmark had to be purchased, and the cards could get expensive)
Calvin Ball (Mornington Crescent)
Classic Cheat Code (Down, A, B, Up, Up, Right was a card about identifying their sources)
Collectible Card Game (the puzzle cards)
Conviction by Contradiction (Alibi)
Darker and Edgier (The back of Season 2 cards indicated cracks in the veneer of the city's exterior. One of the more thought-provoking ones included the implication that it was essentially a world of those with Asperger's, and those that didn't were ostracized similar to what some with Asperger's experience in Real Life.)
Ear Worm (the Whipsmart Ice Cream song)
Entry Point (entering the codes from cards)
Everything's Better with Cows (Whipsmart Ice Cream)
Everything's Better with Penguins (Penguin Sums)
Fifteen Puzzle
Fox Chicken Grain Puzzle (Bar Crossing)
Game Show Problem (Jaunty Paul)
Knights and Knaves (Nio is the basic version, while Murder at the Liars Club has 3-4 of each)
Last Lousy Point: (Three cards from the first season have yet to be solved; one, Riemann, is a mathematical challenge that hasn't been solved in over a hundred years of existence. Luckily, they're not required to complete the game.)
Love Dodecahedron (California)
MacGuffin (the Receda Cube)
Magic Square Puzzle
Match Three Game (Countered)
Mondegreen (well, a card about identifying them)
Moon Logic Puzzle (many black and silver cards, plus a few of lower difficulty)
Only Smart People May Pass (e.g. locks were puzzles, which should be a problem because...)
- Planet of Hats (everyone in the city was an expert at puzzles)
Pirates (on many cards)
The Plan
Puppet Master
Queens Puzzle
Real Life Writes the Plot (The game was expected to last only eight to nine months, so Mind Candy needed to add plot on the fly)
Riddle of the Sphinx
Shout-Out (the card ARG! has questions about other alternate reality games)
Thousand Origami Cranes (Sadako Sasaki)
Three Plus Five Make Four (Volume)
Towers of Hanoi (Multiple iterations, even)
Twelve Coins Puzzle (Poison Pill has a variant with one weighing of any number of pills from five jars)
Twenty Minutes Into the Future