What is your process? Everything I've tried so far makes file that is poor quality, usually audio/video sync problems. I've been trying to convert to .AVI or .MPG - I'm not familiar with mkv. It seems like the encoding programs have half a million settings to fiddle with, and after playing with it for a while, I gave up.
I'm on Windows 2000, using DVD-Shrink, VirtualDub (for DVDs) and DivX.
Insert your DVD and have DVD-Shrink assess it. Normally, I'm just interested in the main movie, so if you want menus and extras, you may have to do some of your own research here. Select "Re-Author" so DVD-Shrink will allow you to recompress the movie and shrink it to fit a certain target size ... but I prefer to keep the quality, so I leave it full size.
Now this is an important step. Edit-->Preferences-->Output Files. Uncheck the "Split VOB files into 1GB size chunks". This way you'll get one huge VOB file, instead of several smaller ones. Run the utility, you'll get a bunch of miscellaneous DVD files, in addition to your VOB. The VOB is the only one you are interested in.
Find a copy of VirtualDub that can read a VOB file. Normally, a VOB is some sort of non-standard MPEG2 file, which will result in a synchronization/pack error (or something similar). This version of VirtualDub can read it like any other file. Select DivX as your compression scheme, configure your bitrate for whatever size/quality you desire, then save as an AVI. Done!
For those who like ripping television shows, each title should show up as a separate VOB file. This means every episode is ultimately stored as a separate AVI file. No menus, no commercials, no FBI warnings ... just the content!