A news story posted in Bluesnews.com indicated that several new developments were on their way for HL2 from Steam. They would be correcting a "sound stuttering bug" which was the result of texture thrashing on your video card or AGP memory. They also promised to release the Source SDK. And, they also promised a surprise.

That surprise turns out to be... drum roll... Half Life 2 deathmatch! The Steam forum had this post on the subject, along with a teaser image.