Speaking of biometrics. c't comparison article.
As might be expected, the consumer-level biometric systems aren't tamper-proof.
[Face recognition]: FaceVACS-Logon can be outfoxed with a short video clip of a registered person.
[...]
[Capacitive fingertip print comparisions]: Although this according to the manufacturer's statements should have been impossible we were able several times to reactivate by simply breathing upon them traces of fat left by fingerprints upon the sensor's surface, thereby overcoming the biometric protection of the system. We cupped our hands above the scanner and within the shell thus formed breathed gently upon the sensor's surface. Meanwhile on the screen of the biometrically-protected computer we were able to see the contours of an old fingerprint slowly reemerge.
[...]
[Iris recognition comparisons]: What was interesting though was that all iris images taken by the system showed a bright spot in the middle of the pupil. This fact gave us the idea that - besides fulfilling the requirement of acquiring a green light by the system - we might in our next attempt at outwitting it show the system's camera human digital iris images printed on paper that had a small hole cut into the middle and behind which were placed the hidden pupils of actual human beings.
[...] etc.
They also discuss getting in by tapping into USB lines and using a bit of Perl code.
It's a good read, though the English translation is a bit rough in places.
Cheers,
Scott.