Which is only going to work if you have a Mac which was introduced in 2011 or later.
If your Mac is of an earlier generation then video AirPlay will not function. This is due to fact that Apple decided to implement this feature on processors that can support this in hardware ( Intel QuickSync Video) - this basically means the "Sandy Bridge" family of core i3, i5, and i7 processors or later.
For those of you who are lacking the most up to date Macs then apparently AirParrot will achieve the desired results.
I have the ATV1 (unhacked) and the ATV2 with Firecore makes it much more useable. I think most Apple content is too expensive, so with FireCore, I can run almost ANY video format, with XBMC (and IceFilms), I can stream almost unlimited content, and there is a browser for internet... all the stuff Apple SHOULD have provided us. And after the "hack" it looks exactly the same as before (just more tabs), so you don't have to be a gearhead to use it. And lots more features that I didn't mention.
I highly recommend it. Only caveat is there is no jailbreak yet for ATV3. But it is coming. Best $30 you can spend. And even MacWorld endorses it with 4.5 Stars, so it is safe and you can do a factory reset to get rid of it if you want to.
fduvall
PS- @Slaphead - I am installing AirParrot now. Thanks for the tip. My 2009 MBP has a 1TB HD, an SSD and all the RAM that it can take, so not upgrading for a while!
Hey, I'm not making any guaranties here. I don't have an Apple TV of any vintage, so I've not used or tested it. I've just read from reliable sources that this is a viable alternative.