Imagemagick is a wonderful suite of tools that allow people to do lots of interesting things with images. Combining it with very minimal scripting knowledge lets one easily automate processing of large batches of images.
I used ImageMagick's compare tool to highlight in red the difference between 286 sequential images captured over 24 hours. I then used IM's convert tool to remove all other colors, create a transparent background, and finally stack each image onto the next.
Avconv was then used to turn these into a short 10 second video.
It's not terribly clear, but it does highlight the path(s) worms are taking. The large blob of red that shows up at the top is sunlight penetrating the first inch or two of topsoil/debris.
Very little attention to any sort of detail has been taken with this. This was a terribly fun distraction from documenting the actual setup - which I should really finish up in the next week or two : ) Regardless, I am constantly amazed at the amount of blood sweat and tears that are freely available in the software world.