Valve's Source Filmmaker
Valve have announced the Source Filmmaker, their tool for creating animated films in a very intuitive way.
Portal 2: Lab Rat - Part One
Read part one of Portal 2: Lab Rat, a comic created by Valve to bridge the old and new game in the series.
Portal 2 - Turret Trailer
Valve spills the beans on the technical aspects of the turrets encountered in Portal 2.