Multimedia Player for Windows 8

Arguably the most popular free and open source utility for playing a plethora of video and music file formats on Windows and Mac (including DVDs of course) is VLC. After installing this free program, it will be added to the context menu in Windows 8, so you can right click any music or video file to play it. Or you can set up AutoPlay to launch your DVD in VLC when you insert the disc. VLC offers plenty of playback options for the basic user, advanced features for the power user who wants to stream the DVD over a home network, and more.

GOM Media Player

Another popular free desktop program that will play DVDs on Windows 8, and virtually every media file that VLC can, is GOM Player. It works similarly to other media players, and some would argue it provides a more crisp picture when viewing DVDs. It too has an insane amount of features available to tweak so you can get the perfect playback experience. It also has an official remote control app for iOS and Android devices.

GOM isn't open source and I'd be remiss if I didn't bring up that during the install it tries to install bundled crapware. Usually it's either AVG or Ask toolbar. Just uncheck the option when installing as Windows 8 already has built-in antivirus protection via Windows Defender, and you definitely don't need a worthless toolbar like Ask.com cluttering up your browsers.

KMPlayer

Like VLC, KMPlayer is a versatile open source multimedia application for playing DVDs on Windows 8. And like both VLC and GOM, it contains its own internal codecs and is able to play virtually any media file you throw at it. It's fast, and doesn't take up a lot of computer resources. It was recently purchased by Pandora and has new features to organize video, music, cover art, and an upcoming app store.