Pressing Ctrl+shift+P (default key setting) takes a DOF (Depth of Field) screenshot. It takes the object you're looking at and makes it the focal point. Then everything else in the distance or closer is made out of focus directly proportional to its distance away from the focal point. This is supposed to simulate the way our eyes' focusing mechanisms work.
EDIT: However, some screenshots look better than others. I'd experiment before posting a DOF that's totally out-of-focus in which case the point is lost.
