background blur (DOF simulation) script
This script should make out-of-focus areas (bokeh) even more blurred, so that main subject stands out and even can be made sharper. Though DOF should already be relatively shallow, or in other words, the blurred bokeh must be already present. Therefore, it probably won't work with photos made with compact cameras (if it's not a macro-shot) or DSLRs with small apertures. But this script can make a photo made with DSLR's kit lens look like it was shot with far more expensive optics! IMO it is most suitable for portraits but could be used with other shots also.

