In the spirit of my memento-mori.sh, I've written a script to sleep randomly 0-10 minutes and take a screenshot & webcam shot. Obviously many of the values are specific to my own computer (such as the names in /proc, where in ~/ the pictures are sent to, and the use of ImageMagick, jpegoptim, and OptiPNG), but it should be easy to adapt to your own computer:

#!/bin/sh
set -e
if grep open /proc/acpi/button/lid/LID?/state > /dev/null
then
CURRENT=`date +%s`;
SLEEP=$(( $CURRENT % 10 ))
TIMEOUT="m"
sleep $SLEEP$TIMEOUT
import -quality 100 -window root png:$HOME/photos/webcam/xwd-$CURRENT.png
fswebcam --resolution 1280x1024 -S 2 -F 3 ~/photos/webcam/$CURRENT.jpg
optipng -o9 -fix `ls -t ~/photos/webcam/*.png | head -1`
jpegoptim -m50 `ls -t ~/photos/webcam/*.jpg | head -1`
fi

This would be called from one's crontab like so:

0,10,20,30,40,50 * * * * ~/bin/bin/sousveillance.sh

My original script ran every hour on the hour, but I discovered that this was so predictable that I was beginning to work-around it by switching to a more kosher good-looking application, and wasn't frequent enough anyway. Hopefully the randomized version will work better.