MakeMKV ($50, 30-day free trial) has a simple little name, and there's no big trick to transcoding a video from one container format to another. If that were all this utility did, it would be worthwhile, but boring. The discussion gets more interesting when you consider its ability to rip DVDs and (in the full, paid version) Blu-ray movies to your hard drive.
MakeMKV is easy to use. Insert a disc, let the program analyze it, then save it to your hard drive in the free Matroska video container format. The program could make it a bit easier to choose the location, and defaults to copying everything when you'll usually only want title 0, but those are minor irritants considering what the program does. For detailed instructions, see "How to Rip a Blu-Ray Disc With MakeMKV."
Note that the copy process takes roughly the duration of the movie and the program rips files as they exist: There's no option to compress them further. For that, you'll need a program such as Ripbot264. Also, you'll need to install a Directshow filter for MKV or use a player that supports the format natively such as the free VLC or MPlayer.
You can use MakeMKV for free for 30 days, but to continue with the Blu-ray ripping after that costs $50. Not a bad deal, reallyit's nice not having to drag your discs around to watch a Blu-ray movie on the road.
Note: The "Try it for free" button on the Product Information page takes you to the vendor's site, where you can download the latest version of the software.