I've had my Apple TV for almost 2 years and I've had Mountain Lion for about 8 months. When I installed Mountain Lion I was thrilled to be able to do Airplay Mirroring and I got it to work a few times, but my issue is that the Airplay icon on my Macbook Pro rarely ever shows up in the top menu. I have Airplay mirroring activated on both devices and they're both up to date. The only thing is my laptop can hardly ever read my Apple TV, and the troubleshooting guide on the Apple site is no help. This is really frustrating and any help on how to alleviate this is welcome.