YouCoob is an application that allows you to download videos from youtube, but it does one by one without access to the website.
It's very easy. Copy the URL, paste it into the text box, click the 'download' button and wait for a few seconds.
The configuration options are very low, in fact you can only select the output folder and if you want to monitor the YouTube link and download them automatically.
The output format is measured on the website's format. This is an old video if it will be FLV, although it is a new HD video, it will be MP4
YouCoob is a useful program for users who want to save videos from YouTube to watch them offline.