DVDDecrypter (free) to copy the film, as has been said above. Easy to get the director’s cut or foreign language version though – avoid this by enabling stream processing and deselecting everything but the video and appropriate audio. Fairly quick…
DVDVideoSoft’s Free Studio Manager (the clue’s in the name) to convert the ripped .VOB file to the format of your choice. Not fairly (or even slightly!) quick (but you can choose to download the toolbar to make it faster).
Apparently…
Legally perhaps a rather grey area – what if you only do this with DVDs that you’re keeping and want to be able to view them on a tablet – but strange that some DVDs now come with an MP4 of the film available for download or even (I think) on the DVD itself…