Lolock is a project mainly written in Python, it's free.
Clicking the mouse without first entering a key combo causes the computer to lock itself and take a picture with it's webcam.
LOLOCK README
Required Modules: -- pyHook -- pythoncom -- mailer -- VideoCapture & PIL
Install: 1.) Install the required modules 2.) Open video.py in a text editor (vi, notepad, etc) 3.) Head down to the settings section and make any appropriate changes
Usage: 1.) Double click video.py, it should perform a countdown...use this time to minimize the window. 2.) Walk away from PC inconspicuously 3.) Wait for some stupid person to try and mess with your computer. 4.) ??? 5.) Profit
Note - To override the lock and exit out of lolock perform the magic key sequence, (ALT+J). This can be changed by modifying the KeyID if statement...I was a little too lazy to actually make it modular.
Troubleshooting:
Good luck!