Rip DVDs on a Mac with MacTheRipper and Handbrake Software

Ripping DVDs (geek-speak for copying onto your Mac's hard-drive) is good for making a backup of their content, or watching them on your Mac.

Steps

Download MacTheRipper and Handbrake. You can get these for free online.
Insert the DVD into your drive and use MacTheRipper to rip the whole DVD to your hard drive.
Use Handbrake to encode Add Lyrics to Your iPod Video on your hard drive. This will result in a faster encode time since it is reading the data from your hard drive instead of the disc. You can select the two-pass encoding option on Handbrake to have a better-quality DVD when you are done, this option does take longer though. The most common option for the encoding format is h.264 (also x264), this format has the best quality and results in a .mp4 file when you are finished. This file can be played in QuickTime, iTunes, and any other video player that plays mpeg files.
Remember that it is also possible to rip directly off Start a DVD Collection with handbrake. Note: MacTheRipper is not needed for this.

This works on any DVDs, copy-protected or not, but you should respect the copyright law in your country.
In the US, you may be able to rip one copy of copyrighted material for your own use under the concept of Fair Use.
Circumventing DRM is illegal in and of itself, regardless of ownership of the IP or intent after disabling the DRM method. Read up on the DMCA and then contact your congressman!
Don't use this technique for piracy. Ripping a DVD for your own collection may be fine. Making your entire collection available for the whole Internet to download is illegal and not very cool.