We'll get this way out of the bit first: there is new Half-Life 2 video content detailing a short 30 seconds or so of the docks scene from the E3 footage. The video is available on Steam, and it should also have made its way round various worldwide mirrors by now. That's not the really interesting part about this story though.
A couple hours before the Docks video was released over the service, some inquisitive chap over at the halflife2.net forums discovered the name of the file before it even existed. The line, hl2-docks.exe - located with a hex editor in one of Steam's 400MB gcache.gcf files - prompted an enormous wave of speculation over what its presence could signify. The community got to work, pouring over each line as word spread to the Steam community forums, where work also went under way to discovering the key to the 'mysterious' filename.
Eventually, someone figured it out. Replacing the G-Man video file name (hl2-g-man.exe) with that of the Docks file in a hex editor, users were then able to launch the new video hours before it was released by Valve. How was this possible? Well, speculation is rife, but the solution seems to point to the way Steam goes about downloading content in the background. Many noticed that once the G-Man video had finished transferring on Monday night/Tuesday morning, Steam still appeared to be updating the Half-Life 2 Movies section of the client, yet once the transfer died down, there were no new entries. This means that Valve attempted to sneak the docks file past us before they'd even mentioned it, stored it on our computers and then waited until last night to let us at it.
Why would they have taken this action? Could be a tactic to try and make it look like Steam actually works. Either that or it seems a bit of a sly move designed to simply relieve stress on the servers, it's just too bad for Valve that they didn't hide it a bit better - anybody with a bit of savvy and a hex editor should be able to pull this off. Heck - we managed it! By getting us the file early in the background, there won't be a mad rush as thousands all attempt to squeeze the file down the pipes at once. Stands to reason they'd do it again too, which is why once Steam transfers ceased just after the Docks video was officially released (or rather, unlocked) by Valve, a new discovery was made - HL2-Kleiners_Lab.exe... nudge nudge, wink wink.