Hopefully iPad owners may find it extremely useful :)
VLC for iPAD is freely available on app store...now you can play your mkv, avi and other video files easily without pain of converting!
VLC is a free and open source cross-platform multimedia player and framework, that plays most multimedias files and various streaming protocols.
It is simple to use, yet very powerful and extendable.
VLC has all codecs built-in. It comes with support for nearly all codec there is. And what is more it can even play back the file or media if it is damaged! Missing or broken pieces are no stop to VLC, it plays all the video and audio information that's still intact.http://applidium.com/en/news/vlc_media_player_available_for_the_ipad