I keep forgetting this, so I'll put it here for everyone (including me) to see:

  mencoder dvd:// -o movie.avi \\
-oac mp3lame \\
-ovc lavc \\
-lavcopts \\
vcodec=mpeg4:mbd=1:vqmax=10:lmax=10:keyint=130:vpass=1:turbo \\
-sid 3 -aid 130 \\
-vf scale=720:405,expand=720:576:0:25:1 \\
-spuaa 4

For the second pass, change "vpass=1:turbo" to "vpass=2".