I haven't worked on this for a while, but the applescript that I just pushed works with Plex client version 0.9.5.4 (under Mavericks) and PMS version 0.9.7.12.
Here is a demo:
http://www.youtube.com/watch?v=UF-fKfgkHfw&feature=youtu.be
Unfortunately, I am not able to update the script to work with Plex Home Theater and the new version of PMS, since the new PMS does not work on my Mac Mini (which runs SL on 32 bit).
I wouldn't mind seeing something setup to work with Ubuntu. :)
This was quite easy to do on OS X (with the power of applescripts and the speechrecognition server). I'm not sure it would be that easy to implement on Ubuntu.
I've just come across this, it sounds awesome. Sadly im on a mac mini but would be tempted to buy a microphone if its worth it? I have an android phone with tasker and can now control my lights through voice, would be great to throw in plex control also!!
Hmm, maybe you could fork the script and extend it with support for your lights :)? Check out the demo: http://www.youtube.com/watch?v=UF-fKfgkHfw