I rip audio mp3s of a lot of commentaries for DVDs that aren't mine and sometimes listen to them when I'm not watching the movie.
now lets pretend for a moment i would like to know how you'd do that?
what!?
I watch dvd commentarys with subtitles the cool ship has sailed!
I use a program called Audio Hijack, it's only compatible with Macs. Alternatively, download Audacity (for free) and LAME Mp3 Encoder (also free), run a male-to-male input jack from your headphone out to your line in and hit record. Start movie, go watch another movie and by time that one is done, your recording should be finished too.