the-cavalry/light-locker — pull request #16 by cavalier38 (2013-10-10 20:56:21+00:00)
Title: Lock session when X screensaver kicks in.

Use the X11 Screen Saver Extension for detection and add a commandline-switch (--lock-after-screensaver=) to configure the delay (time=0..n) or disable the behavior (time=-1).