Actually, this bit of business is designed to keep track of the comings and goings of employees using facial recognition instead of punchcards, but there is no reason why you can't use it to protect the house during the holidays.

Model CVJB-G107 features dual cameras (creating a 3D image that prevents false matches using a simple 2D photograph) , night vision, a 3.5 inch TFT display screen, touch keypad, USB and Ethernet port for TCP/IP connections, the ability to register up to 500 faces, and a verification process that supposedly takes less than a second. Using all of this it can store up to 150,000 attendance records of employees, as well as determine which of your relatives are allowed to attend the holiday party this year. [Chinavision via TRFJ]