Brand new Israeli startup BubblePLY has created an easy tool for adding text or link comic-book style bubbles to videos from popular video sharing sites. Tell it the link to a video on YouTube, Google Video, Metacafe and others, and then add your own content. The video is saved and can be shared via a link or embedding on a web page. See the demo here, and an example is here (there seems to be some problem with embedding right now).
This is way too much work for me, but my guess is that some MySpacers will find this compelling.