Download and Convert Videos from YouTube, Vimeo, Dailymotion and other online video sites - ClipGrab

ClipGrab is a free software for downloading and converting online videos from many sites like YouTube or Vimeo. ClipGrab can download from the following sites: YouTube, Clipfish, Collegehumor, Dailymotion, MyVideo, MySpass, Sevenload, Tudou, Vimeo.

Downloaded videos can be converted to the following file formats: WMV, MPEG4, OGG Theora, MP3 (audio only), OGG Vorbis (audio only).

ClipGrab isn’t limited to the sites listed above, because many more sites are supported "unofficially" through the automatic site-recognition of ClipGrab - just try it! ClipGrab can also download HD videos from sites that have support for high definition (e.g. YouTube or Vimeo).

ClipGrab Installation:
Open the terminal and type following commands:

sudo add-apt-repository ppa:clipgrab-team/ppa
sudo apt-get update
sudo apt-get install clipgrab

After successful installation go to "Dash  Home" and search for "clipgrap" to open the application

There are many more application through which you can download youtube videos ...

Download or Stream Video/Audio files from Youtube - Gmediafinder
Graphical tool to Download and Convert YouTube Videos - CaC
Download videos from YouTube.com - youtube-dl