HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded DVD to MPEG-4 converter, available for MacOS X, Linux and Windows.

Supported sources:

• Any DVD-like source: VIDEO_TS folder, DVD image or real DVD (encrypted or unencrypted, but protection methods other than CSS are not supported and must be handled externally with third-party software), and some .VOB and .TS files
• PAL or NTSC
• AC-3, DTS, LPCM or MPEG audio tracks

Outputs:

• File format: MP4, MKV, AVI or OGM

Xbox Media Center (XBMC) is apparently some software for the Xbox to do better media browsing and supposedly it's better than Front Row. Okay, Front Row is kind of silly and probably there's a better way to do media browsing. XBMC has been ported to the Mac OS X.

An article giving a couple ways to rip DVD's under Linux.