TF2 Edge Profile

This video (I recommend watching in full HD to see the details) shows an ImageJ processed sequence. The reason for doing this is to view the game without the textures getting in the way, thus allowing us to see the edges of characters, objects, and world geometry.

Team Fortress 2 is notable for the artists making each characters silhouette unique. This leads to unrealistic character proportions, but easy character recognition while gaming. A departure from the normal attempt at realism in order to make the game more successful.

If interested read this [pdf] Valve design document explaining their rendering technique and style choice.