Valve are introducing the Perpetual Testing Initiative for Portal 2 with this new amusing trailer.
Portal 2 - Valentine Trailer
Valve have shown us they're true romantics, with this special trailer for Portal 2.
Half-Life: Raise the Bar
Half-Life: Raise the Bar is a fan-made short film inspired by the Half-Life franchise.
Source Filmmaker - Valve Favorites
Valve are showcasing some of the best short animations created with their new Source Filmmaker software.