Movgrab is a command-line movie downloader for sites like YouTube. It has no dependencies; everything that's needed should be there in the tar.gz package. Movgrab can connect through an HTTP proxy, can output the download to stdout for piping into another program, and can fork into the background to free up the console. When forked into the background, its progress can still be seen in a ps list.
Videomanager is a Web-based video manager. It's not a Youtube/Vimeo clone, it just provides the core functionality of uploading, converting, and displaying videos. Commercial support is also available, as well as enterprise features like distributed rendering, tracking, and live streaming.