Adrian Hon is co-founder and CEO at Six to Start, specialising in gamelike stories and story-like games for the web, mobile, and real world. Clients have included Disney, the BBC, Channel 4, and Penguin, and Six to Start has won multiple awards including Best of Show at SXSW. He also writes about technology for The Telegraph, is writing a Kickstarter-funded book and blog called A History of the Future in 100 Objects, co-organises the Hive Mind Challenge and is the founder of Transmedia London. Perplex City was a worldwide alternate reality game/collective puzzle card game/treasure hunt that ran from 2005 to 2007, involving a £100,000 prize and 512 puzzle cards containing clues and rabbitholes to an extensive online world. This talk will provide an overview of the game, along with thoughts on why it worked, why it didn't, and lessons for the future.