This Team Fortress fan animation created with Source Filmmaker is a cool tribute to the ZombiU CG trailer.
Team Fortress 2 - Meet The Pyro
Valve have released a brilliant new Team Fortress 2 character-centric short animation, this time for the Pyro.
Portal 2 - Boots
The science of the boots used in Portal 2 is explained in this latest video from Valve.
Portal 2 - Turret Trailer
Valve spills the beans on the technical aspects of the turrets encountered in Portal 2.