I love Half-Life 2. I love it. It's the perfect package of storyline, music, immersive environment, and gameplay. This music video uses Half-Life 2 as a realtime 3D engine for moviemaking - a technique called machinima.
I posted it because (a) it's very well done, (2) the music - "So Cold" by Breaking Benjamin - is rockin' and (3) I love Half-Life 2.