This is Easily done with the fabulous program "Handbrake".
Look at it at this website: http://handbrake.fr/ Its cross platform and works pretty good. It converts any DVD into m4v files that are playable on android and Ubuntu PC's as well as on Windows and Mac, Iphone and others.
Install it by adding a ppa to your system:
sudo add-apt-repository ppa:stebbins/handbrake-releases
sudo apt-get update
sudo apt-get install handbrake
But sometimes a DVD isn't easily read. In that case you can convert all separate .VOB files. That has a disadvantage that episodes of the DVD are split into separate files.
To join these files easily without spending te time to reencode them install gpac:
sudo apt-get install gpac
and use MP4box that is a part of gpac.
Joining the m4v files without reencoding them works like this:
MP4Box -cat File01.m4v -cat File02.m4v File-joined.m4v
MP4Box is cross-platform and works on OSX, however I tried this on Ubuntu Linux with H264 videos created by Handbrake for the iPhone 4S.
This works quite fast as the files are not re-encoded.
Rip subtitles from a DVD.
These srt files can be edited and synced with Gnome subtitles.
Read more: http://www.ehow.com/how_12118662_extract-subtitles-dvd-ubuntu.html#ixzz2mEvbx6YG
These two programs work from the commandline. They produce IDX and SUB files.
Read more: http://www.ehow.com/how_12118662_extract-subtitles-dvd-ubuntu.html#ixzz2mEwl09Cr