Grusom YouTube Downloader allows anyone to easily download videos from YouTube. The videos are stored at the same location the downloader executable is, and they come in the standard YouTube format, which if FLV.
The easiest way to watch FLV files, is to download and install VLC Mediaplayer.
Kep in mind, that YouTube downloader can download any video from YouTube, except those which require you to confirm your birth date.

The license of this software is Freeware, you can free download and free use this video downloader software.