Half-Life: Raise the Bar is a fan-made short film inspired by the Half-Life franchise.
Valve have announced they will release their Source 2 engine for free to content developers.
Portal 2 - Authoring Tools Open Beta
The universally acclaimed Portal 2 is getting a level editor. Valve has launched an open beta for the game's authoring tools.
Portal 2 - Boots
The science of the boots used in Portal 2 is explained in this latest video from Valve.