http://www.icn.ucl.ac.uk/facetests/index.php
Vison, Memory and Face Recognition

• Prosopagnosia Research Center
• Institute of Cognitive Neuroscience, UCL
• Department of Psychology, Harvard

I just did this and was really surprised at how shockingly badly I did on 2 of the tests.

Please note their "Privacy Policy" as they ask for username and email address and basic area.

It's pretty interesting!