This has been going on since around May 2004 (or so I have been informed).
Its an ARG. An ARG is an Alternate Reality Game. It's basically in the form of 256 puzzle cards, where you have to solve the puzzles, and then enter the answer on the website. There are different levels of difficulty, ranging from red (easiest) through to silver (most difficult).
Perplex City is a town somewhere, they can only contact us through "Mind Candy", an earth company, and through the internet.
The goal of the puzzle cards is to find the "Receda Cube", which was stolen from Perplex City. The person to find this cube wins $200,000 (£100,000). It is based in the UK, but is spread over lots of countries. Mainly the US and the UK now though.
I can't explain it very well, however these sites offer great information.Firebox - Perplex City
. You can purchase cards here too.The Perplex City homepageWikipedia's indepth explanation
I only started playing this in November last year, and have grown completely addicted. The majority of players seem to be in the UK, but the number in the US is expanding, and Australians seem just as addicted.
Just wondered if anyone else here is as addicted as I am, and of course I wanted to plug it, because its an awesome game, and the puzzles are great fun to solve.
I recommend signing up to the Perplex City website, as there are a couple of cards on there that are free, and give you a taster of how the puzzle cards are done.
Take a look!