I just posted a new YouTube video on the Darwin Channel in which Darwin explains the symbiogenetic origin of complex cells using sushi as a visual example. The direct link is here.
Another useful video is one that I posted a long time ago and it has gotten buried under dozens of others. It is called "Darwin eats a hamburger" and it ties several crucial themes in biology together: nutrition (the dangers of eating too much fat), global warming (raising cattle releases a lot of greenhouse gas), and evolution (why we crave fat). In this video, Emma Darwin also speaks from behind the camera. The direct link is here.