Also, the demos that come with Ogreaddons project. However, while I have received a patch for it, I have not applied it yet do to loss of free time. if you want the patch, IM me and I'll forward it to you. However, the patch only updates the CEGUI demo, to be current with recent Ogre and CEGUI.
You can, however, build the theora demo with Ogre 1.2 and CEGUI 4.x and it should go smoothly. Sadly, I don't really support that project anymore, it was more a proof of concept. You can, however, use it as a basis for a new plugin, or simply make it a static lib decode Theora/Vorbis streams simplifying its usage. As long as you stick with LGPL terms if you use the codebase.
