How do I calibrate an Apple TV Display? I am familiar with using the Display Calibration Assistant.  I have used it on other external monitors before.  Connected to my living room TV via AirPlay using Apple TV.  The colors are all off.  When I open the displays menu, I am able to open the calibration assistant for the built in display, but not my external Apple TV display.  I can see other profiles for other external monitors, but I cannot select them.
I use the THX tune up app on iOS to calibrate my AppleTV over airplay. I've not found a way to get OS X to calibrate things further, but to my eyes, this workaround has been good enough with default settings on OS X.