Valve have announced the Source Filmmaker, their tool for creating animated films in a very intuitive way.
Source Filmmaker - Valve Favorites
Valve are showcasing some of the best short animations created with their new Source Filmmaker software.
Dota 2 - Cinematic Trailer
Valve have released an action packed cinematic trailer for their new game, Dota 2.
Portal 2 - Boots
The science of the boots used in Portal 2 is explained in this latest video from Valve.