okle is a KDE DVD player based on ogle. It supports DVD menus, different languages and subtitles.

You can install it with
klik://okle (klik client must be installed, see http://klik.berlios.de/)

It is only a 500 KB download. I have tested it in Kanotix BH9, but it should also work in the newer Knoppix versions.

Greetings,
probono