Dynpres is a digital signage program (Dynamic Slides Presentation) which is free, GPL and multiplatform. Since it uses bash and LaTeX to generate slides

Pros:

• Totally unattended (reads RSS sources, online graphics, shared folders, etc...) and beautifully formatted slide
• Highly reliable and tweakable
• Quickly deployable over an inlimited number of clients around the globe

Cons:

• Basic knowledge of bash scripting needed

As an example, you can download the PDF product and a video from a real digital signage screen working. Furthermore, there is a link to download the code.

[PDF] Dynpres example product

[VIDEO] Dynpres - Dynamic Presentations

It's GPL! You can download it here:

[TAR.GZ] dynpres