Have a good look at the portraits above. Do they look familiar, but maybe not quite on the spot? Or do they actually look twice as familiar? Probably both.
The reason is that those portraits are not a simple representation of Hollywood stars (that would take care of the familiar part), but a mesh-up of two different stars (and that takes care of the a-bit-off part). Photoshop master gesichtermix mashes up faces of celebrities using Photoshop and it is really hard to take your eye off the resulting portraits.
At first look, you probably see one of the two personalities who make up the portrait but something just done not add up. A deeper, longer look will reveal traces of another person. My favorite is the De Niro/Spacey mesh up – it definitely calls for a remake of face/off.