Motion menus have video playing underneath the buttons to amuse viewers while they're making their menu selection. Video menus come with the same caveat as audio menus: when they're short and repetitive, they get irritating. Plan on using video clips of at least one minute for your video menus, or generic videos like clouds blowing or flags waving where it isn't obvious that they're restarting.
Essentially, a video menu is just like a regular menu, but instead of inserting a still image as background, you insert a video. For a complete recap, review “Using Full-Screen Titles” in Chapter 10, particularly the section “To select an image background.” Here, I'll just cover the highlights.