I've tried to record from supernovatube with Replay Media Catcher and it appeared to be an http:// .flv video.

How to rip http .flv videos:
FAQ: How to record/download/capture/save Macromedia/Adobe Flash .FLV video HTTP stream from embedded player
Getting/Capturing/Downloading .FLV flash videos streamed through the http protocol

The only problem here is that the URLs have timestamps and they expire quickly. When you find such a URL with say freeware URL Snooper, you can copy-paste it into any download manager even a free one, but you should do it fast!