Valve show a grittier more realistic use for Source Filmmaker with a trailer for Counter-Strike: Global Offensive.
The first minutes of the original Half-Life are brought to life in this live action short, Half-Life: Origins.
Portal 2 - Boots
The science of the boots used in Portal 2 is explained in this latest video from Valve.
Portal 2: Lab Rat - Part Two
Read the second part of Portal 2: Lab Rat, the comic released by Valve as a tie-in into the new game in the series.