My use of multimedia in Assemblies supports the narrative action rather than replaces it. I have tried using Google Docs here to store the slideshow for a Junior School (whole school) Assembly of 7-11 year olds.
At present, the Google Presentation tool does not seem to support builds (or animated Gifs), and I have had to use YouTube Videos as the video images (which is okay, as I derived them from there in the first place!). It gives you the gist. Oh, and the video for “We want to see…” is missing
See if you can make up your own narrative for the assembly.