Playing Spotify (or really any OS X app) Through AirPlay or AppleTV
note: This is for the Mac OSX version of Spotify, for the iOS app: how to use the Spotify iphone/ipad app with AppleTV
I've been using Spotify a lot lately. I also recently purchased an AppleTV. While entertaining some guests, I was thinking it might be fun to play Spotify through the sound system connected to the AppleTV.
It was then that I found a neat little feature of the latest OS X version (Mountain Lion 10.8), the ability to play all audio from your Mac to the AppleTV. Caveat: this might be limited to only certain Macs, I'm using a late-ish model Macbook Air so YMMV.
Just choose "System Preferences" -> "Sound" and choose the AppleTV as the sound output for the Mac. Then all application sounds will play over AirPlay, including Spotify or any other music app. Not earth-shattering, but definitely neat. I didn't see this mentioned in the searches I did on Google for this so I thought I'd write it up as a quick tip. Hope this helps someone.