I mentioned before about schools setting up digital signs, and wanted to post an update. One school that I've worked with has two signs set up, both connected to regular PCs. One is a 24 inch monitor, the other is a 40 inch LCD TV; both are 1080p resolution.
The staff member who builds the "morning announcements" bulletin also makes a PowerPoint file that is set to loop on each screen. Unfortunately at this point she has to manually transfer the file to each computer using a USB drive.
This plan is still to set up more computers around the school, connected to 42 inch LCD TVs mounted on the walls, and use Xibo Open Source Digital Signage.