A video is worth a thousand words.

Let's say you're having a tough time visualizing the fetal circulation in your head and diagrams just aren't cutting it. Google has a cool feature that allows you to search for Flash videos by using the filetype:swf modifier. For example if I wanted flash videos on the fetal circulation, I typed fetal circulation filetype:swf.

Here's a nice flash animation on the fetal circulation that I found with this Google search.