A robot faction is introduced into the Team Fortress 2 equation, via this amazing new trailer by Valve.
End of the Line
End of the Line is an animated short film created with Source Filmmaker.
Source Filmmaker - Valve Favorites
Valve are showcasing some of the best short animations created with their new Source Filmmaker software.
Portal 2 - Boots
The science of the boots used in Portal 2 is explained in this latest video from Valve.