PyTube is a GUI tool to download videos online from Video-sharing websites like Youtube, Google videos. Not only can it download files, PyTube can search for videos and help you to convert the videos to your format of choice. Also, can manipulate videos like Apply Audio into Video, Merge videos, resize videos, create ringtones to your mobilephone, rotate videos etc.

youtube-dl is a small free opensource command-line program to download videos from YouTube.com. youtube-dl is a platform independent tool that works on UNIX, Linux, Mac OSX and Windows. The latest version of Youtube-dl is 2008.08.09 and requires the Python interpreter, version 2.4 or later.

If you've ever wanted to save those videos you watch on YouTube, you've no doubt looked to (or wondered about) various Firefox plugins or programs to do the job. Well, no need to go hunting and installing. The whole process is a lot easier than you think.

Clive is Command-line and fullscreen console program that extracts videos from YouTube, Google Video and other video sites. It supports embedded video extraction, and can be used with an external encoder (e.g. ffmpeg) to re-encode the extracted videos to different video formats (e.g. avi, mpeg, flv).

youtube-dl is a small command-line program to download videos from YouTube.com.
Install youtube-dl in Ubuntu

You can see YouTube videos everywhere nowadays: on blogs, Google search results, even some news sites. From time to time, you can even manage to find something interesting. This article will show you some Linux tools you can use to save and convert YouTube videos.

SAN FRANCISCO, Nov. 11 — Intel plans to announce a family of microprocessor chips on Monday that it says will speed the availability of high-definition video via the Internet.

GNOME’s Totem Movie Player now includes a plugin for searching and playing YouTube videos without leaving the player, and without Flash. It’s installed by default in Ubuntu 8.04, and works fabulously!

"...In an effort to improve all Google services, we will no longer offer the ability to buy or rent videos for download from Google Video [...] After August 15, 2007, you will no longer be able to view your purchased or rented videos..."