Well you can say one thing about Valve; they don't have to do much to drive the internet wild.
Half-Life 2 got a patch recently, which appeared to be a localisation patch for Korea, and accidentally changed the game settings to Korean in the process. Naturally, people looked far further into it...
The problem has since been rectified, but that doesn't stop people thinking there is more than meets the eye to the whole deal. The reason they are so excited is that a patch to Portal 1 started off the Portal 2 ARG (Alternate Reality Game); a chain of clues and storyline hints that eventually led to the announcement of the sequel.
Naturally, if it happened to Portal 1, everyone is assuming that it will happen to Half-Life 2 in order to tease Half-Life 3 - a Mythical game which according to the internet will solve world poverty or something.
Valve have since fixed the problem, and early attempts at finding an ARG in the files have failed. Looking across the internet sees a rollercoaster of emotions, with people finding unusual sound files (another trick from Portal 1), only to realise they are not codes, just common things like radiation suit noises (the Korean sounds seem very different, oddly).
It does beg the question though; if Valve did a Half-Life 3 ARG, where would they start? Would we even know? Tell us what you think below!