It sounds like an announcement regarding the acquisition of Valve is imminent. Valve is the brains behind the "Source" gaming engine -- a popular engine that powers games such as Half Life 2 and Portal. Valve is also the creators of Steam, a distribution service that game developers can take advantage of to distribute their games to users.
It's unclear how much Google is paying for the company, or what exactly it's interested in, but I would suspect it has something to do with the in-game advertising. Google has been interested in doing this for a long time now -- they even acquired a company called Adscape Media in 2007 to help get their foot in the door.
It will be interesting to see what Google does with the company -- what do you think?