The method I am about to describe can help you take excellent screenshots that look like sketches of whatever you are looking at. First, go into a game and throw either a frag, plasma, or firebomb grenade near whatever you want to take a "sketch" of. Then, go into theater mode and move your camera inside of the explosion caused by the 'nade. The screen should be entirely white. Then, slowly move the camera to the outer edge of the explosion. If done right, this method will make it so that the outside world appears a sketch. Now, just point it at your subjects, and click away! Ex1- Taken by me, EZappa. Ex2- Taken by DJ MENACE UK.
They look somewhat close to sketches, but couldn't you just easily use Photoshop or some other picture editing program to make an even better effect? Or is this for File Shares? I might try this sometime, very cool find! Never knew that before. Just assumed that if you took the picture it would just a be the explosion!
To answer your question: I made this guide with the intention of helping players do some "in-game" photo editing, without having to upload the picture onto their CPU and shop it.