Commerical for a game called Gears of War featuring a cover of Tears for Fears' Mad World by Gary Jules (which you might remember from Donnie Darko). The ultraviolence and poignance is an interesting juxtaposition.
Update: Greg Allen uncovers the original music video for the aforementioned Mad World cover, directed by Michel Gondry.
Update: So, the long GoW video posted above was created by a fan using the original version (also at YouTube) directed by Joseph Kosinski (David Fincher consulted on it as well, I guess). (thx, chris)