The best way to do is to play the DVD in VLC, a free media player. VLC media player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs, VCDs, and various streaming protocols. It can also be used as a server to stream in unicast or multicast in IPv4 or IPv6 on a high-bandwidth network.

But I have seen lot of original movies that can't be played in VLC and then you have to rely on commercial tools like WinDVD, PowerDVD, etc. But these commercial players also have their own limitations and they can't play region coded movies, so most users try to rip the DVD. Ripping not only takes time, but you also loose subtitles, etc.

Thankfully, now there is a better solution for the same: DVD43 (DVD for free). DVD43 is a free DVD decrypter that runs in the background and decrypts DVDs on the fly. To install just run the setup file which installs DVD43 and leaves a happy face icon on your task bar. DVD43 will run in the background and decrypt movies on the fly. Insert the DVD you want to play and wait for DVD43 to detect it (smiley face turns green). Start your favorite DVD player and enjoy watching region coded DVD's without any hassle.