Why So Serious? (The Dark Knight alternate reality game)

Why it works

Fifteen months before The Dark Knight reached cinemas, Warner Bros. and 42 Entertainment started letting fans dig the film out for themselves. Joker cards left in comic shops pointed to a defaced campaign site for Harvey Dent, where every email address submitted erased one pixel from the first image of Heath Ledger's Joker. From there the game spread across fictional Gotham websites, phone numbers, text messages, live events and real-world scavenger hunts, including mobile phones baked into cakes, as players enlisted as the Joker's henchmen, Dent campaigners or copycat Batman vigilantes. It is studied as the high-water mark of the alternate reality game as a marketing form: even the first look at the villain was a prize the audience had to win together, so fans became the distribution. USA Today put participation at 10 million players in 75 countries. At Cannes in 2009 it took the Cyber Grand Prix, a year after 42 Entertainment won the same prize for Nine Inch Nails' Year Zero.