Whenver I see that acronym, I think Anti-Replicator Gun from SG-1 and Atlantis.
. Google Wave link if you're lucky enough to have it
Basically, the gist of it is that Valve released a random Portal update with the description:
Updates to Portal have been released. The updates will be applied automatically when your Steam client is restarted.
Changed radio transmission frequency to comply with federal and state spectrum management regulations
People quickly noticed there was a new achievement titled "Transmission Received" that is triggered when you bring the radio from the room where you wake up out with you to the first red button. A new light on the radio turns from red to green when you do this, and it starts playing Morse code instead of the Still Alive muzak.
The achievement indicates you've completed 1/26. There are now 25 other radios hidden throughout the next levels, and you have to find them, pick them up, and walk to wherever their light turns green. Some have more Morse code, others made some weird distorted sounds.
Naturally I immediately set out trying to get the achievement, figuring the prize would be had when you got that. I spent a few hours, got myself to 20/25, and gave up to see what everyone else had figured out. In the time it took me to find those radios, the people at Steam forums had found out this was a full fledged alternate reality game.
Enterprising forumgoers found each of the sounds the new radios broadcast in the game's resource files, labeled as dinosaur1.wav through dinosaur26.wav. Those that were in Morse code were translated.
interior transmission active external data line active message digest active
system data dump active user backup active password backup active
beep beeeep beep beep beeeep beeeep beeeep beep beeeep beep beep
(If you treat THIS as Morse code, it gets translated to "LOL")
5. turns out to be the MD5 hash of "The quick brown fox jumps over the lazy dog" which people discovered by googling it.
The remaining sounds are actually pictures encoded as audio. I'm not going to go into too much detail here, but if you want to see them, they're all here
. Each image is contains at least one number or letter. This turned out to be another MD5 hash, which turned out to be the MD5 hash of a phone number near Seattle. The number is (425) 822-5251. (DO NOT CALL THIS unless you know what you are doing.) People who dialed into the phone were greeted with the sounds of a modem.
Turns out on the other end of this number is an old BBS line. You have to dial in with an old-fashioned dial-up modem, and then use a terminal program to communicate with the other computer. The username/password was given in morse code above: backup/backup.
Basically, the other computer dumps a bunch of ascii art
into your terminal. As far as everyone knows so far this is as far as it goes.
People are speculating that this means that HL2:EP3 and Portal 2 will be combined somehow, or that some announcement is going to be made on the 11th regarding Portal 2 (because the version of GalDOS on the other end of the BBS line is 3.11 - I guess nobody's ever heard of Windows for Workgroups