Handbrake - easily convert DVDs to MPEG4 video files - http://handbrake.fr/
Update: I had some trouble with programs ripping a particular VOB file from a DVD with bad audio video synchronization. I tried several programs without luck. In the end, I used the "Wizard" in VLC player and transcoded from there. The quality probably isn't the best; however, it works. Besides, sometimes you don't need the highest quality, e.g. if it's destined to a little Flash video on the web.
Not tried: Front end for ffmpeg. Windows. https://sourceforge.net/projects/ffmpeg-batch/
tags: encode, transcode, divx, xvid, sync, fix, problem, avi