I recently learned that there are editions of the Roku that have a headphone port on the remote control, allowing you to plug your normal headphones into that port and have the audio output there rather than on the television. This effectively turns ordinary headphones into wireless headphones and allows you to watch without disturbing (or being disturbed by!) others in the room.
If the plex app for mobile (iOS, android) could have audio from other Plex instances redirected to it, or potentially streamed independently and kept in sync with the video through some other means, this would allow for similar functionality, and would be amazing!
Like this post if you like this idea to get it voted up! :rolleyes: