Basilisk

Concept

Players compete individually to score points by scanning QR codes. Some codes ("Basilisks") are penalties, and prevent the player scanning more codes for various amounts of time. Because of variations in the style and placement of the codes, it's possible to deduce (by trial, error, observation and discussion) which codes are safe.

For example, perhaps all red codes are dangerous, all codes found on the underside of placemats are safe, and the code printed in the shape of a parrot is a severe penalty.

Setup

Print off a number of QR codes with URLs pointing to a game server. They should be in various styles. Hide them around the space. Set a time limit, optionally set up a highly visible leaderboard. Brief the players and start the game.

Strategy

You'll want to find and scan barcodes without letting other players see you do it, since that will reveal the hiding place of the code and negate your advantage. There are elements of bluff here, because you might be able to convince players that a safe code is a basilisk, or that a basilisk is safe. There's also the possibility of collaboration to discuss results and locations, but it will have to eventually end in a backstab since there can be only one winner.

Aggressive tactics like grabbing a basilisk and shoving it between a player's active scanner and the thing they're trying to scan are entirely legitimate (and rather cool) until they get annoying, at which point they should be banned.

A Big Visible Leaderboard would be nice, so people know who to gun for.

Technology

Android phones have an existing app that scans QR codes and goes to the URL embedded in them using the phone's browser. I'm sure other smartphones have similar apps. I was thinking of a simple Rails app with QR code URLs like http://fire-hazard.net/basilisk/53734 which either increments a player's score (using cookie sessions), or displays a basilisk and increments their can't-scan-anything timeout.

Inspiration

See the faq: http://www.ansible.co.uk/writing/c-b-faq.html