Here is yet another way to produce a little divx file (using mencoder) that don’t need to be of an exellent quality (eg. for old mangas episodes):
mencoder -chapter 1 -dvd-device /dev/cdroms/cdrom0 -o /path/to/myfile.avi -ovc\
lavc -lavcopts vcodec=mpeg4:vqscale=10 -sws 5 -vop scale=320:240 -oac mp3lame \
-lameopts cbr:br=128:ratio=5:vol=6 dvd://9
Note: you have to change the dvd-device according to your setting as well as the number after dvd:// to find the track you want to rip