You might have heard a lot of people talking about the new features of HTML5, and one that has brought a lot of interest is the <video> element that some people think that will avoid the use of Flash once and for all (at least Steve Jobs thinks so).
But back to the topic, HTML5 video and CKEditor. What about that?
Ok, here we go, this is a plugin sponsored by DM Logic that makes using the <video> element as easy as an old <img>, you can insert, edit, use the context menu, etc... the dialog allows to specify the poster image, the dimensions (they are automatically adjusted according to the preview) and two source files, so that both the browsers that use the WebM format (Chrome, Firefox and Opera) and the ones that support only h264 (IE9 and Safari) can view your videos. Here's a short video showing how it works.
v.1.3 26/08/12: Fixed problems with IE9, wrap the video in a <div> to avoid the problems with <p>. It's compatible with both CKEditor 3 and CKEditor 4