Update 2: Even though fans may have been disappointed with the payoff from last night's countdown, there are still a few little treats on the site. If you view the page's source info, you can see an ASCII version of Aperture Science's logo. Also, if you click on the picture of the potato on the bottom of the page, you'll get to hear a little sound clip from GLaDOS. They may not have been worth losing sleep over, but they're still pretty cool little extras.

Thanks for the tips, Sam and Brian A!

First Update: Well, we're surprised, but not really in the way we were hoping. Valve's countdown drew such a crowd that its site seems to have crashed. You can stop trying; we made it through and its just a thank you page to everyone who contributed in the ARG. Uh...you're welcome. In case you can't get through, here is what you're missing.

Original Story: A mysterious email in the GI inbox contains a Web address within a "scanned" Aperture Science memo. Valve's designers sure are enjoying themselves with this ARG business.

The memo invites readers to go to this URL, which points to a "Surprise Deployment Initiation System" countdown set to expire at 8pm Central time tonight. Is this the first wave of Portal 2 DLC?

The memo also references Pneumatic Diversity Tubes, which were shown off in pre-release videos and didn't make it into the game at launch. If this is DLC with a new set of puzzles built around those vacuum-like tubes, I know what I'm doing tonight.