FairUse Wizard is an open source (GPL) DVD backup tool. It can directly encode fron DVD (without ripping) to XVID/H264(video)-AC3/MP3/Vorbis(audio)-AVI/OGM/MKV(container).
It also has internal codecs (doesn't need VFW sh*t).
It would be great to have a portable version...
http://www.fairusewizard.com - Official website
http://www.fairusewizard.com/Release/fu-src.zip - source code
It breaks CSS encryption on the DVDs to back them up to DivX format. This makes this software illegal under US law. This website and SourceForge.net are both US-based, so we can't touch this.
Sometimes, the impossible can become possible, if you're awesome!