mplayer can do lots of neat stuff, do a "man mplayer" and read the docs, printed out its about 50 pages to print do: man mplayer | col -b | lp
for example, want to rip a dvd into divx you'd this just for a simple example:
mencoder dvd://1 -oac mp3lame -ovc lavc -lavcopts vcodec=mpeg4:vhq:vqmin=2:vbitrate=900 -o <yourfilename.avi>
that will give you a divx copy in whatever scale the dvd is written with, you can also rescale it to be smaller or bigger and crop the image, lots of options, mencoder does decoding/encoding and is part of the mplayer package