Half-Life 2 -- The Next Chapter

Via GameSpot (full article here):

The good news is that Valve is in the final stages of prepping Half-Life 2: Aftermath, the first expansion for Half-Life 2, due out later this year. Valve likes to describe Aftermath as a new "episode" for the franchise, and we know that it picks up immediately after the events of the main game.

The Q/A goes on to say that Alyx will have a much bigger role in the new chapter, and that more emphasis will be placed on interaction with NPC’s (non-playable characters) to get tasks done.  It’s expected to be released before the end of the year.  Sweet.