ARG stands for Alternate Reality Gaming, also known as Chaotic Fiction. I'm going to thank Helenae/Liandra for introducing me to the genre through the marketing of Cloverfield. Clues are left on the "official" Cloverfield website as well as other "in-game" websites that are providing backstory to what looks like an exciting movie. A similar marketing method is used to promote The Dark Knight movie, although it seems to be moving much slower and offering less in the way of clues at this point.

Essentially what you have are interactive puzzles taking place in real time involving real people. Considering how many people we've had take an interest in The Game I thought some of you might be interested in a very modern, and very fun, style of puzzle gaming.

From what I've seen the most recognized and respected site on these types of games is Unfiction.com, and I'm having a blast reading some of the threads on their forums. If you like puzzles, or marketing, or both, you might also.

Nine Inch Nails album Year Zero also has an ARG behind it. There has been a series of clues left on thing like tour t-shirts, USB flash drives left in the bathrooms at their performances, and on buttons and things like that. It's really in depth too as to figure out the clues there are things like spectrograph analysis to be done. Really cool concept, it kept me hooked reading through the slew of websites about the Year Zero world for about a week.

I heard about the Year Zero stuff, and there's a section of Unfiction devoted to it. I took one look at the website, saw the bits that would require spectrograph/code analysis and new I was over my head so I didn't pursue it. Looked like a lot of fun, though.