Apple TV on a Mac. Is it possible?

It was. Back in 2008, someone did it. Lifehacker has an article about it, but that was for OS X Tiger http://lifehacker.com/369305/run-apple-tv-on-your-mac-with-atv4mac).

Times have changed, and so has Apple TV's software. I wonder if it would be possible today. I know there are many media managers out there, and I know that Front Row can easily be resurrected on OS X Lion, but I really want to have ATV's OS on a Mac.

Is it possible? I'm sure it is. So the question really should be. Is anyone up for it?

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via images.apple.com

Also, I know that iPads, etc. can AirPlay to an Apple TV. Is that feature software based or hardware based? If it is purely software based, would it be possible to display and iPad on a Mac?