It was an ARG (Alternate Reality Game) which took place on the web and was supplemented by large-sized cards which contained puzzles on them. You solve the cards by entering in the solution on the website, gaining points and notoriety. I think a great "game" would be the PerplexCity puzzle card, where you could zoom into the cards to see high detail, ability to "email" the card to yourself so you can print them (or link em to your online account and print them via the website), and allow you to "solve" the puzzles within the app itself. Mindcandy, are you listening?! There's a huge market for your 200+ puzzle cards already produced! They could even, for example, allow purchasers of the app (few $) about 20 or 30 cards. Then allow in-app purchasing of other "random packs" to complete your set. Just saying...